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HP 6825A User's Manual

1. fxd film 6K 1 1 8W fxd film 21 5 1 1 8W Switch rotary 3 sections Diode zener 6 2V Not Assigned Diode zener 6 2V CEA T 0 CEA T 0 0698 3476 0698 3430 3100 1941 1902 1221 1N825 1N825 1902 1221 Voltage and Current Control Plug in Board 28480 06825 60021 fxd mica 30pF 5 300V RDM15E300J3S 0160 0181 fxd cer 390pF 1 500V DD472 0160 0474 fxd mica 30pF 5 300V RDM15E300J35 0160 0181 fxd cer DIuF 1KV C023A1024103MS38 CDH 0150 0012 fxd cer 3900pF 5 500V fxd mica 30pF 5 300V 0160 2723 0160 0181 RDM15E300J3S fxd mylar 001uF 10 200V 292P10292 PTS 0160 0153 fxd tant 2 2uF 20Vdc 150D225X0020A2 DYS 0180 0155 fxd mylar 015uF 10 200V 292P15392 PTS 0160 0194 fxd elect 100uF 6Vdc 30D 107G006CC2 DSM 0180 1734 6 6 A2C14 CR1 2 CR3 4 CR5 CR6 CR7 8 CR9 CR10 CR11 12 CR13 14 CR15 17 CR18 24 Ki K2 3 Q1 4 fxd mica 30pF 5 300V Diode Si 200mA 75V Diode Si 250mW 200prv Diode Si 200mA 75V Not Assigned Diode Si 250mW 200prv Stabistor Si 10prv 400mW Diode Si 200mA 75V Diode Si 250mW 200prv Diode Si 200mA 75V Not Assigned Diode Si 200mA 75V Reed Relay Reed Relay SS NPN Si SS PNP Si SS NPN Si fxd film 1K 1 1 8W fxd ww 714 196 4W fxd film 1K 1 1 8W fxd film 6K 1 1 8W fxd ww 10 24K 05 6W fxd film 6K 1 1 8W fxd
2. CHANGE 17 In Table 1 1 under DC Output Isolation change float voltage to read from 300 Vde to ground to 120 Vde to ground zi 7 SAFETY SUMMARY The following general safety precautions must be observed during all phases of operation service and repair of this instru ment Failure to comply with these precautions or with specific warnings elsewhere in this manual violates safety standards of design manufacture and intended use of the instrument Hewlett Packard Company assumes no liability for the customer s failure to comply with these requirements BEFORE APPLYING POWER Verify that the product is set to match the available line voltage and the correct fuse is installed GROUND THE INSTRUMENT This product is a Safety Class 1 instrument provided with a protective earth terminal To minimize shock hazard tha in strument chassis and cabinet must be connected to an elec trical ground The instrument must be connected to the ac power supply mains through a three conductor power cable with the third wire firmly connected to an electrical ground safety ground at the power outlet For instruments designed to be hard wired to the ac power lines supply mains connect the protective earth terminal to a protective conductor before any other connection is made Any interruption of the protec tive grounding conductor or disconnection of the protective earth terminai will cause a potential shock hazard that
3. e Adjust oscilloscope to observe rise time of one squarewave The waveshape should be within the tolerances shown on Figure 5 7 output should change from maximum t rated negative value to maximum rated positive value in less sf o than 5Qusec BPS A UNDER TEST GENERATOR f Check the fall time of one squarewave It should be almost identical to the rise time except for inversion 5 34 Output impedance To check the output imped ance proceed as follows a Connect test setup as shown in Figure 5 B b Set MODE switch to POWER SUPPLY RANGE switch to X4 and turn unit on c Adjust VOLTAGE contro until front panel meter reads 20V Figure 5 8 Output impedance Test Setup d Set AMPLITUDE control on Oscillator to 10 volts Ein and FREQUENCY control to 100Hz sinewave e Record voltage across output terminals of the power supply Eo as indicated on AC voltmeter f Calculate the output impedance by the follow ing formula 5 35 Temperature Coefficient Definition The change in output voltage per degree Centigrade change in the am bient temperature under conditions of Zout ER O constant input ac line voltage output volt Ein Eo age setting and load resistance 5 7 5 36 The temperature coefficient of a power supply is measured by piacing the power supply in an oven and vary ing it over any temperature span within its rating Most HP power supplies are rated for operation from 0 C to 550C The pow
4. Due to the voltage drop in the load leads it may be necessary to readjust the constant current crossover limit setting in the remote sensing mode 3 40 REMOTE PROGRAMMING CAUTION A programming device or programming resistors must be connected to the appropriate rear term inals and the rear terminal strip cover must be in place when the instrument is in use Also if resistive ladder networks are utilized to program the constant voltage constant current outputs ensure that make before break switching is em ployed so that the BPS A s voltage and current programming terminals are not momentarily opened If the programming terminals should open the output voltage current will rise to a value that might damage the load 3 41 The constant voltage and constant current outputs of the BPS A can be programmed controlled from a re motely located device such as HP 6940A Multiprogrammer or HP 6941A Multiprogrammer Extenders Either a resis tance or voltage source can be used as the programming de vice The wires connecting the programming terminals on the rear of the BPS A to the remote programming device should be twisted or shielded to reduce noise pickup 3 12 Resistance Programming Constant Voltage A programming resistor Rpy connected as shown in Figure 3 6 can be used to control the voltage output or gain pro vided that the MODE switch is in the POWER SUPPLY or the VARIABLE GAIN AMP position Resistance program ming
5. 2 1 INITIAL INSPECTION 2 2 Before shipment this instrument was inspected and found to be free of mechanical and electrical defects As soon as the instrument is received proceed as instructed in the following paragraphs 2 3 MECHANICAL CHECK 2 4 if external damage to the shipping carton is evident ask the carrier s agent to be present when the instrument is unpacked Check the instrument for external damage such as broken controls or connectors and dents or scratches on the panel surfaces if the instrument is damaged file a claim with the carrier s agent and notify your local Hewlett Packard Sales and Service Office as soon as possible see list at rear of this manual for addresses 25 ELECTRICAL CHECK 2 6 Check the electrical performance of the instrument as soon as possible after receipt Section V of this manual contains performance check procedures which will verify in strument operation within the specifications stated in Tabie 1 1 This check is also suitable for incoming quality control inspection Refer to the inside front cover of the manual for the Certification and Warranty statements 2 7 REPACKAGING FOR SHIPMENT 2 8 To insure safe shipment of the instrument it is recommended that the package designed for the instrument be used The original packaging material is reusable If it is not available contact your local Hewlett Packard field office to obtain the materials This office will also furnish the add re
6. D CAE OPERATING AND SERVICE MANUAL BIPOLAR DC POWER SUPPLY AMPLIFIER HP MODEL 6825A Hp Part No 06825 90001 OPERATING AND SERVICE MANUAL FOR SERIALS 13244 00101 AND ABOVE For Serials Above 13244A 00101 a change page may be included ONE YEAR WARRANTY This HP product has a one year warranty Please replace the first paragraph of the warranty statement on the inside front cover with the following This Hewlett Packard hardware product is warranted against defects in material and workmanship for a period of one year from date of delivery HP software and firmware products which are designated by HP for use with a hardware product and when properly installed on that hardware product are warranted not to fail to execute their programming instructions due to defects in material and workmanship for a period of 90 days from date of delivery If HP receives notice of such defects during the warranty period HP shall repair or replace software media and firmware which do not execute their programming instructions due to such defects HP does not warrant that the operation for the software firmware or hardware shall be uninterrupted or error free Printed March 1974 CERTIFICATION Hewlett Packard Company certifies that this product met its published specifications at time of shipment from the factory Hewlett Packard further certifies that its calibration measurements are traceable to the United States Nationa Bureau
7. G E Semiconductor Products Dept Syracuse N Y Eldema Corp Compton Calif Transitron Electronic Corp Wakefield Mass Pyrofilm Resistor Co Inc Cedar Knolls NA Arrow Hart and Hegeman Electric Co Hartford Conn ADC Electronics Inc Harbor City Calif Caddell amp Burns Mfg Co Inc Mineola N Y Hewlett Packard Co Palo Alto Div Palo Alto Calif Motorola Semiconductor Prod Inc Phoenix Arizona Westinghouse Electric Corp Semiconductor Dept Youngwood Pa Ultronix Inc Grand Junction Colo Wakefield Engr Inc Wakefield Mass General Elect Co Electronic Capacitor amp Battery Dept Irmo S C Bassik Div Stewart Warner Corp Bridgeport Conn IRC Div of TRW Inc Semiconductor Plant Lynn Mass Amatom Electronic Hardware Co Inc New Rochelle N Y Beede Electrical Instrument Co Penacook N H General Devices Co Indianapolis ind Semoor Div Components Inc Phoenix Arizona Robinson Nugent Inc New Albany N Y Torrington Mfg Co Van Nuys Calif Use Code 28480 assigned to Hewlett Packard Co Palo Alto California CODE MANUFACTURER ADDRESS Transistor Electronics Corp Minneapolis Minn Westinghouse Electric Corp Elmira N Y Fairchild Camera and Instrument Mountain View Calif Birtcher Corp The Los Angeles Calif Sylvania Electric Prod Inc Mountainview Calif IRC Div of TRW Inc Burlington lowa Continental Device Corp Hawthorne Calif Raytheon Co Comp
8. a Connect load resistance high range and ditfer ential voltmeter as illustrated in Figure 5 1 b Set MODE switch to POWER SUPPLY and RANGE switch to X4 Turn CURRENT control fully clockwise c Adjust front panel VOLTAGE control ciock wise until differential voltmeter indicates maximum rated output voltage d Aliow 30 minutes warm up then record differ ential voltmeter reading e After 8 hours differentia voltmeter should change from reading recorded in step d by less than 11mV pot wiper jump effect may add 20mV f Repeat steps a through e with low range X1 load resistance connected as shown in Figure 5 1 Set RANGE switch to X1 g Observe differential voltmeter reading Differ ence in voltage reading between step d and e should be less than 2 5mV pot wiper jump effect may add 5mV NOTE If remote programming is employed the potenti ometer wiper jumper effect is eliminated 542 CONSTANT CURRENT TESTS 5 43 The instruments methods and precautions for the proper measurement of constant current power supply char acteristics are for the most part identical to those already described for the measurement of constant voltage power supplies There are however two main differences First the power suppiy performance will be checked between short circuit and full load rather than open circuit and full ioad Second a current monitoring resistor is inserted be tween the output of the power supply and
9. line via Z common through resistor R60 10 3W Also with A1K1 deenergized an open circuit is present at the emitter of A3Q1 When power is applied relay ATK1 will not become energized for approximately 0 2 seconds due to RC time constant R32 R37 C2 Thus the open circuit condition is present at the emitter of A3Q1 at initial turn on The 20V unfiltered supply voltage however caus s transistors A304 and A3G5 to be forward biased Consequently transistors A302 and A3Q3 are turned on drawing current away from the bases of driver transistors A3Q12 and A3Q13 respectively effectively turning these stages off After the delay approximately 0 2 seconds has elapsed relay A1K1 becomes energized removing the 2 common path to the HI OUT terminal and connecting 2 common to the emitter of A3Q1 causing the collector of A3Q1 to drop to about 0 1V For this condition the for ward bias for transistor A3Q4 is removed causing A3Q4 to turn off which in turn causes transistors A302 and A3Q3 to turn off removing the clamping action at th bases of A3012 and A3Q13 Driver transistor A3012 or A3Q13 will now conduct depending upon the magnitude and polar ity of the error signal 4 37 At turn off the 20V unfiltered supply voltage is removed but relay A1K1 remains energized for approxi mately 1 seconds due to stored energy When it becomes deenergized the L I common connection from the em itter of A3Q1 is removed and the Hi OUT line
10. N J Fairchild Camera and Instrument Corp Mountain View Calif Daven Div Thomas A Edison industries McGraw Edison Co Orange N J Signetics Corp Sunnyvale Calif Bendix Corp The Navigation and Control Div Teterboro N J Electra Midland Corp Mineral Wells Texas Fansteel Metaliurgical Corp Union Carbide Corp Electronics Div Mountain View Calif UID Electronics Corp Hollywood Fla Pamotor Inc Pampa Texas General Electric Co Schenectady N Y General Electric Co Nela Park Cleveland Ohio General Radio Co West Concord Mass LTV Electrosystems inc Memcor Com ponents Operations Huntington Ind Dynacool Mfg Co Ine Saugerties N Y National Semiconductor Corp Santa Clara Calif Hewlett Packard Co Palo Alto Calif Heyman Mfg Co Kenilworth N J IMC Magnetics Corp Rochester N H SAE Advance Packaging Inc Santa Ana Calif Budwig Mfg Co Ramona Calif G E Co Tube Dept Owensboro Ky Lectrohm Inc Chicago Il P R Mallory amp Co Indianapolis Ind Muter Co Chicago lil New Departure H yatt Bearings Div General Motors Corp Sandusky Ohio Ohmite Manufacturing Co Skokie Iii Penn Engr and Mfg Corp Doylestown Pa Polaroid Corp Cambridge Mass Raytheon Co Lexington Mass Simpson Electric Co Div of American Gage and Machine Co Chicago lil Sprague Electric Co North Adams Mass Superior Electric Co Bristol Conn Syntron Div of FMC Corp Homer City Pa
11. NO t _ VT AIS AIG AI AIG BIO A20 A21 ojejelelelglo A ww AB BS AIO AI AI2 AB Ad jejelelelele BPS A GZ KO 2 AIS AIG AJ7 AIG AI9 ASA ejelejelelelo Al AZ 3 S pronon AB A9 ADAN Al2 AIS Ai eigleleletele BPS A Cj NO 3 A 5 AIG AIT AIG AI9 A20 A2I ejejejejeiele 1 NOTES L ALL THREE UNITS MUST BE OPERATED IN THE SAME MODE 2 UNITS 2 AND 3 MUST BE FLOATED NOT CONNECTED TO CHASSIS Figure 3 11 Parallel Connections 357 AUTO SERIES AND AUTO PARALLEL CONNECTIONS 3 58 The following paragraphs describe the connections required for combining BPS A s in auto series and auto parallel These connections are employed whenever it is re quired to extend the voltage gain or current capability be yond one supply For auto series operation the output volt age of each slave supply varies in accordance with that of the master supply For auto paraliel operation complete control of the output current from one master is allowed Diagrams are included for the strapping connections re quired between master and slaves for both auto series and auto paraliel operations in either case the master must be in the power supply or variable gain amplifier mode and the slaves must be in the fixed gain amplifier mode Also for auto series or parallel operation the master supply s Local Auto switch A2S1 see Figure 3 9 must be in the Local pos ition and each slave supply must have its Local
12. No Chicago Hi CODE MANUFACTURER ADDRESS Thomas and Betts Co Philadelphia Pa Union Carbide Corp New York N Y Ward Leonard Electric Co Mt Vernon N Y Amperite Co inc Union City NJ Beemer Engrg Co Fort Washington Pa Belden Corp Chicago HI Bud Radio inc Willoughby Ohio Carnbridge Thermionic Corp Cambridge Mass Bussmann Mfg Div of McGraw amp Edison Co St Louis Mo CTS Corp Elkhart ind L T T Cannon Electric Inc Los Angeles Calif Globe Union Inc Milwaukee Wis General Cable Corp Cornish Wire Co Div Williamstown Mass Coto Coil Co Inc Providence R I Chicago Miniature Lamp Works Chicago lil Cinch Mfg Co and Howard B Jones Div Chicago ilt Dow Corning Corp Midland Mich Electro Motive Mfg Co inc Willimantic Conn Dialight Corp Brooklyn N Y General Instrument Corp Newark N J Drake Mfg Co Harwood Heights lii Elastic Stop Nut Div of Amerace Esna Corp Union N J Erie Technological Products Erie Pa Hart Mfg Co Hartford Conn Beckman instruments Fullerton Calif Fenwai Inc Ashiand Mass Hughes Aircraft Co Electron Dynamics Div Torrance Calif Amperex Electronic Hicksville N Y Bradiey Semiconductor Corp New Haven Conn Carling Electric Inc Hartford Conn Federal Screw Products inc Chicago ili Heinemann Electric Co Trenton N J Hubbell Harvey Inc Bridgeport Conn Amphenol
13. and current 5 65 In general if the BPS A operates properly in the sampling resistor A2R27 The CURRENT MODE indicator power supply mode it should also operate properly in the A5DS2 lights and a FLAG indication is present high level amplifier mode variable gain or fixed gain amplifier mode at terminal A17 when the BPS A is in constant current op The trouble symptoms listed in Tabie 5 3 isolate the troubie eration During constant current operation stages A205 or to defective components or groups of components function A206 provide the proper level to contro the CURRENT al circuit areas The voltage control stages on board A2 in MODE lamp driver A202 Q3 and FLAG output driver conjunction with the output power amplifier stages on A204 stages for positive or negative output current respec board A3 and the heat sink assembly provide the desired tively i Table 5 3 Overall Trouble Isolation Guide PROBABLE CAUSE a Fuse blown or incorrect rear terminal strip strapping etc see Paragraph 5 66 SYMPTOM No output voltage All modes POWER SUPPLY VAR GAIN AMP FXD GAIN AMP b Main bias or reference voltages defective see Paragraph 5 67 c Relay A1K1 circuit board A2 or A3 or output power transistors on heat sink assembly defective see Paragraph 5 70 amp MODE switch defective Internal positive dc reference defective A2C10 R3 R58 R59 Voltage reference gain control amplifier sta
14. as in fine or load change will cause a corrective voltage to alter the appropriate series regulator positive or negative conduction thereby restoring the load current to some initial value 4 52 Positive current comparison amplifier A2U3 moni tors positive output currents and negative current compari son amplifier A2U4 monitors negative output currents These amplifiers control switching the BPS A between constant voltage and constant current operation In constant voltage operation they are in saturation reverse biasing A2CR13 and A2CR14 and preventing any current contro action in constant current operation they become linear comparison amplifiers allowing BPS A operation as a constant current source Also for current sink conditions they limit the output current to 1 2 maximum rated output through sepa rate control circuits consisting of A2CR3 CHA CR7 CRB CR11 CR12 R28 and R29 Because the two comparison amplifiers are similar only the positive current comparison amplifier is described in detail 4 53 The voltage drop across the current sampling resis tor A2R27 is applied to pin 3 of A2UJ via the front panel CURRENT control A5R1 or the remote programming input terminals Current control through A5R1 local control is achieved with tear terminals A12 A13 and A14 strapped together for positive currents and with A19 A20 and A21 strapped together for negative currents External digital re sistance control can be imp
15. or remote programming input The front panel CURRENT controls or remote programming inputs of all three units are operative and the current limit is equal to the lowest setting The slave units must be floated off ground Instruments can be operated floating up to 300 volts off ground whether operated singlely or in series 3 60 For instantaneous equal voltage sharing resistors R4 R2 or R3 must be equal Since any variation in Ry R2 or R3 will result in a change in the voltage divider ratio and hence the output of the slave supply it is important that these resistors be stable low temperature coefficient 20 ppm 9C or better Also they should have power rating of at least 10X their actual power dissipation The resis tors should be selected at the normal operating voltage levels so that the current through them is about 1 to 2mA 3 61 Auto Parallel Operation Two or more BPS A s can be connected in auto parallel arrangement to obtain an output current greater than that available from a single sup ply Figure 3 13 illustrates the auto parallel connections for three supplies to allow increased output current in con stant voltage operation When this arrangement s used current sharing under all load conditions is permitted under control front paneli CURRENT contro or remote program ming of the master supply Because the CURRENT con trols or remote programming of each slave are operative they should be set to a maximu
16. paragraph 1 15 Shunt resistor A1R53 and standard VOLTAGE control HP P N 2100 3272 A5R2 are removed when the ten turn output voltage control HP P N 2100 1867 is instal led in the A5R2 locatlon CHANGE 1 In Table 1 1 make the following changes Under General Specifications change meters paragraph to read Individual voltage and current meters DC voltmeter accuracy is 3 of full scale AC voltmeter accuracy is 54 of full scale with sinusoidal 100 Hz input AC and DC ammeter accuracy is 6 of full Scale Under Power Supply Specifications change load effect load regulation to read Voltage X1 Range 0 01 5 mV Voltage X54 Range 0 01 mV Change Source Effect line regulation to read Voltage X1 Range 0 01 5 mV Change PARD Ripple and Noise to read Voltage X1 Range 3 mV rms 8 mV p p Voltage X4 Range 10 mV rms 30 mV p p Current 5 mA rms 15 mA p p Under Power Amplifier Specifications add the following to the Distortion Specification Total harmonie distortion THD at full out put is as follows ami ty mt pio A z Au MD A OR HUE UV UI HIP TR SY A FREQ THD pU i MAP RE i 100 Hz 08 kHz 1 d 10 kHz i 35 1 20kHz 1 55 30kHz 2 2 i 40 kHz 5 i ab iio MD ADOG E AP EE ANB c MED MUR GE VB Mp Mu UNI P VG TA ln paragraph 5 12 change voltage specified in step q and u to 1 0 mV In paragraph 5 14 change voltage specified in steps f a
17. ww 25K VOLTAGE Control 2100 3272 1 Switch Toggle SPDT 5A LINE Switch 3101 1605 2 Switch Rotary 3 Sections RANGE MODE Selection Switch 3100 1942 Heat Sink Assembly Electrical Q1 4 Power NPN Si TB1 3 Terminal Block Ribbon Cable Assembly 1854 0264 0360 1766 5060 9662 Chassis Electrical C1 2 fxd mylar 1uF 220Vac 439P 1059220 0160 3679 C3 fxd cer 1uF 500V 41C92B5 CDH 0160 0269 Transformer Power 06825 80091 6 10 Table 6 4 Replaceabie Parts REF HP DESCRIPTION TQ MFR A A1 interconnect and Power Supply l Board Mechanical Heat Dissipator Q1 Q3 NF 207 05820 A3 Power Amplifier Board Mechanical NF 207 2227 B 1205 0033 Heat Dissipator Q6 Q9 Q11 Heat Dissipator Q14 019 Heat Sink Assembly Mechanical Bushing insulator Q1 04 insulator Mica Q1 04 1205 0033 1205 0206 0340 0795 0340 0174 Chassis Rear 5000 9369 Heat Sink 5020 8401 Barrier Strip Board Assembly 5060 9663 Heat Sink Board Assembly Front Panel Mechanical Bezel Meter Control Pane Output Panel Foot Assembly Insulator Binding Post Black Insulator Binding Post Red Knob VOLTAGE Control CURRENT Control VOLTAGE METER switch 5060 0728 0340 0733 0340 0734 CURRENT METER switch 4 0340 1099 Knob MODE select 1 0370
18. 52 2 13 Outline Diagram mene DO 5 42 Constant Current Tests ge se 5 8 2 15 Rack Mounting E 5 56 Amplifier Mode Tests M EN T 5 12 2 17 input Power Requirements cccccccsccserserrsenecansere 2 2 5 60 Troubleshooting SEERY 5 13 2 20 Power Cable ENEE 202 5 61 General dm 5 64 Overall Trouble isolation Procedure sss t i OPERATING INSTRUCTIONS dipsa dee Ma 3 1 5 71 A2 Board Troubleshooting EEN Bis 3 1 introduction ONAR ROA os 5 76 A3 Board and Heat Sink 3 3 Rear Terminals and AC Input cccccsesseececeneceeeees 3 1 Assembly Troubleshooting 5 19 3 5 Operating Controls and Indicators ZE A 5 82 Degraded Performance Probiems een 5220 3 6 Mode Switch See WEE EEN we 3 1 5 84 Repair and Replacement eese BI 3 10 Range EE 3 2 5 86 Covers and Front Panel AEN 5 21 3 12 Voltage Control TE ECA wadi SK 5 92 Rear Heat Sink Assembiy seer seso s BEE 5 22 3 14 Current Control E 3 2 5 98 Adjustment and Calibration DEES E D23 3 16 Voltage Metering EEN 5 100 Meter Zero EEN ERAN 5 23 318 Current Metering osasmeoeeooweonoscowcoocowasononoaneoc OG 5 102 Constant Voltage Calibration 0 0 0 ccc ceann LS 3 20 Turn on Checkout Procedures 93 5 106 Constant Current Calibration een 5 24 3 22 O
19. A2 in order to control the conduction of the output power transistors on the heat sink assembly The A3 board and heat sink assembly stages can be isolated from the voltage and current feedback loops by removing the A2 board from the instrument and providing an external con trol voltage input to the A3 board The following paragraphs describe troubleshooting procedures for the A3 board and heat sink assernbly circuits 5 78 Output Amplifier Stages To troubleshoot the am plifier and driver stages on the A3 board and the output power transistors on the heat sink assembly proceed as fol lows a Remove the A2 board from the unit and remove the load from the output terminals b Connect function generator HP3310A output terminals between the connector side of A3R15 and 2 Set output of function generator for a sinewave of approxi mately 2V p p at 100Hz with a dc offset of 3 5V Connect an oscilloscope to S and S terminals c Turn on power and observe a sinewave output of 40V p p The sinewave should not be clipped or distorted d If either polarity of the sinewave is missing or distorted troubleshoot by tracing the sinewave back to the source Refer to Figure 7 2 Sheet 1 Also check the turn on off circuit Paragraph 5 79 NOTE When troubleshooting the power amplifier cir cuits keep in mind that possible trouble areas exist in the interconnections A1 board W1 and W2 ribbon cables as well as the A3 board circu
20. ADJUSTMENT AND CALIBRATION 5 99 Adjustment and calibration may be required after performance testing troubleshooting or repair and replace ment 5 100 METER ZERO 5 101 The meter pointer must rest on the zero calibration mark on the meter scale when the instrument is at normal operating temperature resting in its normal operating posi tion and turned off To zero set the voltmeter and ammeter proceed as follows a Turn on instrument and allow it to come up to normal operating temperature about 30 minutes b Turn instrument off Wait one minute for power supply capacitors to discharge completely c Insert sharp pointed object pen point or awl into small indentation near top of round black plastic disc located directly below meter face d Rotate plastic disc clockwise until meter reads zero then rotate counterclockwise slightly in order to free adjustment screw from meter suspension Pointer should not move during latter part of adjustment 5 102 CONSTANT VOLTAGE CALIBRATION NOTE The CURRENT MODE light should be off dur ing these procedures 5 23 5 103 Output Zero and Offset Adjustments a Remove top cover to gain access to potentio meters on boards A1 and A2 b Connect DVM to the S and S rear terminals c Short BPS A front panel input terminals Fil IN to LO IN Output terminals HI OUT and LO OUT are open circuited d Set MODE switch to FXD GAIN AMP position Turn CURRENT control fully c
21. Corp Amphenoi RF Div Danbury Conn E F Johnson Co Waseca Minn 6 3 Table 6 3 Code List of Manufacturers CODE MANUFACTURER ADDRESS IRC Div of TRW Inc Philadelphia Pa Howard B Jones Div of Cinch Mfg Corp New York N Y Kurz and Kasch inc Dayton Ohio Kilka Electric Corp Mt Vernon N Y ittiefuse inc Des Piaines ill Minnesota Mining and Mfg Co St Paul Minn Minor Rubber Co Inc Bloomfield N J James Millen Mfg Co Inc Malden Mass J W Miller Co Compton Calif Cinch City of Industry Calif Oak Mfg Co Div of Oak Electro Netics Corp Crystal Lake Itt Bendix Corp Electrodynamics Div No Hollywood Calif Palnut Co Mountainside N J Patton MacGuyer Co Providence R I Phaostron Instrument and Electronic Co South Pasadena Calif Philadelphia Steel and Wire Corp Philadelphia Pa American Machine and Foundry Co Princeton Ind TRW Electronic Components Div Camden N J Resistance Products Co Harrisburg Pa llfinois Tool Works Inc Elgin Hi Everlook Chicago Inc Chicago til Stackpole Carbon Co St Marys Pa Stanwyck Winding Div San Fernando Electric Mfg Co Inc Newburgh N Y Tinnerman Products inc Cleveland Ohio Stewart Stamping Corp Yonkers N Y Waldes Kohinoor inc LLC NY Whitehead Metals Inc New York NY Continental Wirt Electronics Corp Philadelphia Pa Zierick Mfg
22. Eo 0 if Rpy 10 24K Eo 20 48V if Rpy 20 48K 4 50 In the variable gain amplifier mode the BPS A controls the gain of an externally applied dc or ac signal For this mode the internal fixed dc reference voltage is disconnected and the reference gain control circuit attenu ates or amplifies the externally applied signal from 0 to 2X depending upon the setting of the VOLTAGE control ASR2 or remote programming resistance The feedback resis tor s provide a gain of 1 in the X1 range and a gain of 4 in the X4 range Consequently the variable gain is from O to 2X in the X1 range and from 0 to 8X in the X4 range in the fixed gain amplifier mode the gain is controlled only by the feedback resistor s which provide a times 1 gain in the X1 range and a times 4 gain in the X4 range 4 51 Current Comparison Amplifiers Current compar ison amplifiers A2U3 positive and A2U4 negative con trol BPS A operation between constant voltage and constant current by continuously monitoring the voltage drop across the current sampling resistor A2R27 This voltage drop is applied to the current comparison amplifiers via the front panet CURRENT control A5R1 or the remote programming input terminals The other input to the current comparison amplifiers is a stable fixed reference current Any disturb ance in load current whether by variation of the CURRENT control or remote programming input or in the current flow through the sampling resistor
23. LOAD CONSIDERATIONS 3 32 The life and performance of the instrument can be preserved if the following simple precaution is observed when driving reactive loads Always set program the VOLT AGE control for zero output before removing a capacitive load or interrupting an inductive load 3 33 CONNECTING LOAD 3 34 Each load should be connected to the power sup ply output terminals front or rear using separate pairs of Connecting wires This will minimize mutual coupling ef fects between loads and will retain full advantage of the low output impedance of the power supply Each pair of connecting wires should be as short as possible and twisted or shielded to reduce noise pickup If a shielded pair is used connect the shield to ground at the power supply and leave the other end unconnected 3 35 If load considerations require that the output power distribution terminals be remotely located from the power supply then the power supply output terminals should be connected to the remote distribution terminals via a pair of twisted or shielded wires and each load should be separately connected to the remote distribution terminals For this 3 5 case remote sensing should be used Refer to Paragraph 3 39 3 36 Always use two leads to connect the load to the supply regardless of where the setup is grounded This wili eliminate any possibility of output current return paths through the power source ground The supply can also be o
24. RESISTOR cou REPETITIVE d toan SWITCH NOTE 1 Figure 5 4 Transient Recovery Time Test Setup 5 32 To check the transient recovery time proceed as follows a Connect test setup shown in Figure 5 4 Set MODE switch to POWER SUPPLY and RANGE switch to X4 b Turn CURRENT control fully clockwise c Turn on supply and adjust VOLTAGE controi clockwise until front panel ammeter indicates maximum positive rated output current d Close line switch on repetitive load switch set up e Set oscilloscope for interna sync and lock on either positive or negative load transient spike f Set vertical input of oscilloscope for ac coupling so that small dc level changes in power supply output voltage will not cause display to shift g Adjust the vertical centering on the scope so that the tail ends of the no load and full load waveforms are symmetrically displayed about the horizontal center line of the oscilloscope This center line now represents the nom inal output voltage defined in the specification h Adjust the horizontal positioning control so that the trace starts at a point coincident with a major graticule division This point is then representative of time zero i Increase the sweep rate so that a single transient spike can be examined in detail j Adjust the sync controls separately for the posi tive and negative going transients so that not only the recov ery waveshape but aiso as much as possible of the r
25. Temperature Coefficient Output change per degree Centigrade change in am JI bient using an external control resistor Reg at output voltage VO or current ig T C Rp is the tem perature coefficient of the control resistance Rp Voitage X1 Range 25mV 007 VQ 96 T C Rp Vo 5 Voltage X4 Range 1mV 007 Vg T C Re Vo 20 Current 016 19 33uA T C Re lig Fixed Gain Accuracy at 100Hz Low Range X1 1 5mV High Range X4 1 2mV Remote Resistance Programming Variable Gain Ay 8 KRr 10 24 x 1030 cated and Rr is the external control resistance RF 10 24 x 103 Ay where K is the constant indi Sink Current Compliance Maximum current that the supply can sink when con Ay at low range X1 nected to an active load y 4RE Ay at high range X4 Y ibis 10 24 x 103 Variable Gain Accuracy Accuracy in high range at 100Hz using an external control resistance Re at output voltage VO Re is the accuracy of the control resistance Rp 05 MRE Vo 2 5mV Remote Voltage Control Coefficient Fixed gain amplifier mode voltage coefficient Sink current is limited to a value ranging linearly from Voltage X1 Range 1 voit volt t 1 2A OV to 1A 20V Voltage X4 Range 4 volts voit 1 Externally applied voltages to output terminals in ex cess of 25V could damage the instrument Variable gain a
26. The following troubleshooting procedures are performed with power applied to the BPS A while its protective covers are re moved Be careful when performing the procedures as line voltage is alweys pres ent on the power input connector fuse holder and in the power supply rectifier circuits In addition when the supply is on energy available at many points par ticularly the power transistors on the rear heat sink may result in personal injury or death when contacted a Remove covers and A3 board from the instru ment b Remove load and connect a DVM to the S and S rear terminals C Set controls on front panel as follows MODE switch POWER SUPPLY RANGE switch x4 VOLTAGE control fully clockwise CURRENT control fully clockwise Board Isolation Procedure The board isolation pro 5 18 VOLTAGE METER high range DC CURRENT METER high range DC d Turn on power and observe that LINE indica tor lights e Check that turn on off relay A1K1 is operating properly by connecting ohmmeter between A1K1 pin 1 and 2 Ohmmeter should indicate an open circuit If a short circuit zero ohms is present check relay AIK and associated components A1C2 CR4 R32 R37 If open Circuit is present proceed to step f f Turn off power and isolate the turn on off cir cuit on board A3 by lifting the connections from diodes A3CR3 and A3CR4 to the collectors of transistors A302 and A3Q3 respectively Install A3 board
27. a reasonable time to repair or replace any product to a condition as warranted the Customer shail be entitled to a refund of the purchase price upon return of the product to HP LIMITATION OF WARRANTY The foregoing warranty shall not apply to defects resulting from improper or inadequate maintenance by the Customer Customer supplied software or interfacing unauthorized modification or misuse operation outside of the environmental specifications for the product or improper site preparation and maintenance NO OTHER WARRANTY 1S EXPRESSED OR IMPLIED HP SPECIFCALLY DISCLAIMS THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE EXCLUSIVE REMEDIES THE REMEDIES PROVIDED HEREIN ARE THE CUSTOMER S SOLE AND EXLCUSIVE REMEDIES HP SHALL NOT BE LIABLE FOR ANY DIRECT INDIRECT SPECIAL INCIDENTAL OR CONSEQUENTIAL DAMAGES WHETHER BASED ON CONTRACT TORT OR ANY OTHER LEGAL THEORY ASSISTANCE The above statements apply only to the standard product warranty Warranty options extended support contracts product maintenance agreernents and customer assistance agreements are also available Contact your nearest Hewlett Packard Sales end Service office for further information on HP s full line of Support Programs MANUAL CHANGES Model 6825A DC Power Supply Manual HP P N 06825 90001 2 4 91 gt all corrections in the manual according to errata below then check the following table rec your power supply serial number an
28. and connect DVM to S and S terminais g Adjust the function generator output level for a DVM reading of 14 1 0 2V rms h Adjust A1R 13 for 14 1V rms on BPS A front panel voltmeter 5 111 AC Ammeter Calibration a Connect DVM across the 1 2 resistor b Adjust function generator output level for a DVM reading of 1 414 06V rms c Adjust A1R18 for 1 4A rms on BPS A front pane ammeter SECTION VI REPLACEABLE PARTS 6 1 INTRODUCTION 6 2 This section contains information for ordering re placement parts Tabie 6 4 lists parts in alpha numeric order by reference designators and provides the following informa tion a Reference Designators Refer to Table 6 1 b Description Refer to Table 6 2 for abreviations e Tota Quantity TQ Given only the first time the part number is listed except in instruments containing many sub modular assernblies in which case the TQ appears the first time the part number is listed in each assembly d Manufacturer s Part Number or Type e Manufacturer s Federal Supply Code Number Refer to Table 6 3 for manufacturer s name and address f Hewlett Packard Part Number g Recommended Spare Parts Quantity RS for compiete maintenance of one instrument during one year of isolated service h Parts not identified by a reference designator are listed at the end of Table 6 4 under Mechanical and or Miscellaneous The former consists of parts belonging to and grouped by individual assemblies
29. b Apply a SV p p 100Hz squarewave to the A1 HI IN and A LO IN terminals c Connect a 112 5W resistor across H OUT and LO OUT terminals Connect oscilloscope across 152 resistor d Turn on BPS A and observe waveforms see Figure 5 15 Overshoot should not exceed 5V p p Lu 5v Figure 5 15 Overcurrent Protect Test Waveform 5 55 Turn on off Transient Protect To test the turn on off transient protect circuit proceed as follows a Set front panel controls as follows MODE switch POWER SUPPLY RANGE switch X4 VOLTAGE control fully clockwise CURRENT control fully clockwise b Connect a clip lead from base of A3Q1 to ground D c Turn on BPS A Output should be from 0 to 1 5Vdc d Remove clip lead output should be 20V e Repeat steps a through d except turn VOLT AGE control fully cow for 20V output 556 AMPLIFIER MODE TESTS 5 57 Gain and Meter Accuracy Test To check gain and the meter accuracy in the amplifier modes proceed as fol lows a Connect the test setup as shown in Figure 5 16 Use the appropriate low range load resistor Ri b Set BPS A front panel controls as follows MODE switch VAR GAIN AMP RANGE switch X1 fc s um 5 oc PF DQ ONE fully clockwise Con 4 VOLTAGE control CURRENT control fully clockwise VOLTAGE METER low range AC CURRENT METER high range AC c Set generator frequency at 100Hz sinewave and output at 2V peak to peak d Turn o
30. doing To check the current sink performance of the BPS A pro ceed as follows a On the test instrument set controls as follows MODE switch POWER SUPPLY RANGE switch X4 VOLTAGE control fully clockwise CURRENT control fully clockwise b On the source instrument set controls as follows MODE switch FXD GAIN AMP RANGE switch X4 C Turn on test instrument and set output to 20V d Connect function generator to terminals A1 and A2 of source instrument Turn on and adjust source instrument output to 40V p p at 100Hz approximately e Turn off test and source instruments and con nect test setup of Figure 5 13 f Turn on both instruments simultaneously and observe that waveform sampled across the 1 ohm resistor is as illustrated in Figure 5 14 g Repeat test with VOLTAGE control on test in strument set fully counterciockwise Waveform should be same as Figure 5 14 aPs A SOURCE INSTRUMENT aps A TEST INSTRUMENT RX HPIBO OSCILLOSCOPE HP 3304 FUNCTION GENERATOR 3 TEST AND SOURCE INSTRUMENT SHOULD BE SAME MODEL Ht OSCILLOSCOPE FLOATED OFF LINE GROUND Figure 5 13 Current Sink Test Setup Figure 5 14 Current Sink Test Waveform 5 54 Overcurrent Protection Test To check the over current protect circuit proceed as follows a Set BPS A front panel controls as follows MODE switch FXD GAIN AMP RANGE switch X4 VOLTAGE control fully clockwise CURRENT control fully clockwise
31. from short circuit to a value which yields maxi mum rated output voltage 5 48 To check the constant current load regulation pro ceed as follows a Utilize test setup and front panel settings of Paragraph 5 45 b Turn VOLTAGE control fully clockwise c Adjust CURRENT control until front panel meter reads exactly maximum rated positive output voltage d Read and record voltage indicated on differen tial voltmeter e Short circuit load resistor Ry f Reading on differential voltmeter should not vary from reading recorded in step d by more than 450uV 9 Turn VOLTAGE contro fully counterclock wise and repeat steps c through f for negative output voitage 5 49 Rippie and Noise Definition The residual ac current which is superimposed on the dc output current of a regulated power supply Ripp e and noise may be specified and measured in terms of its RMS or preferably peak to peak value 5 50 Most of the instructions pertaining to the ground loop and pickup problems associated with constant voltage ripple and noise measurements also apply to the measure ment of constant current ripple and noise Figures 5 11 and 5 12 illustrate the most important precautions to be ob served when measuring the ripple and noise of a constant current supply The presence of a 120Hz waveform on the oscilloscope is normally indicative of a correct measurement method A waveshape having 60Hz as its fundamental com ponent is t
32. locally front panel VOLTAGE controi or remotely and is accurate to within 0 1 The variabie gain amplifier is non inverting and has a frequency response from dc to 15kH2 Total harmonic distortion is less than 0 1 The fixed gain amplifier is inverting and has a fre quency response from dc to 35kHz 4 4 BLOCK DIAGRAM DESCRIPTION 4 5 Figure 4 1 is a basic block diagram of the BPS A showing the major circuit blocks together with the principle input output signals of each block The sheet numbers correlate the blocks shown on this diagram with the schem atic sheets at the rear of the manual 4 6 The ac line voltage is applied to the power transfor mer and after being altered in level is rectified and filtered The resulting raw de of both po arities is fed to the series regulator output amplifier which varies its conduction pos itive or negative in response to feedback signals to provide the proper output voltage or current During power supply operation this circuit functions as a series regulator to pro vide the proper output voltage During amplifier operation it acts as an output amplifier to provide the proper gain for externally applied ac or de signals The MODE switch allows selection of the power supply mode or amplifier mode fixed or variable gain The series regulator output amplifier is part of a feedback loop consisting of the ampli fier and driver circuits and the voltage and current compar ison amplifier circuit
33. loop when it is energized A capacitor in the circuit holds the amplifier s output voltage rela tively constant during the 8 milliseconds the relay contacts are open during the transfer It is normal for the PS A s output to drift 300 to 500 millivolts during this time If drift is greater than this amount try ad justing A1R61 mized If the setting of A1R61 must be chang ed by more than a slight amount the PS A will then need to be recalibrated following the procedure of paragraph 5 103 Effecil January 1st 1977 10 turn voltage control has been redesig nated Option 009 Make this change wherever Option 007 is mentioned in the manual CHANGE 5 The serial prefix number has been changed to 1808A This is the only change CHANGE 6 In Replaceable Parts Table page 6 11 delete heat sink HP P N 5020 8401 Add heat sink left side HP P N 5020 2583 and heat sink right side HP P N 5020 2584 CHANGE 7 In the replaceable parts list Table 6 h page 6 5 change Ki relay to 6 V AC DC HP P N 0490 1298 CHANGE 8 In the replaceable parts list page 6 9 and on schematic Figure 7 2 Sheet 1 change 3C15 to 0 2 uF 100 V HP P N 0160 0818 ERRATA In the replaceable parts table page 6 5 change AIRS and A1R13 to resistor variable 5 k 1 2 W 10 cermet HP P N 2100 3252 qty 2 slightly while repetitively programming the PS A until the drift is mini Option 007 In the parts list page 6 11 chan
34. of Standards to the extent allowed by the Bureau s calibration facility and to the calibration facilities of other International Standards Organization members WARRANTY This Hewlett Packard hardware product is warranted against defects in material and workmanship for a period of one year from date of delivery HP software and firmware products which ara designated by HP for use with a hardware product and when properly installed on that hardware product are warranted not to fail to execute their programming instructions due to defects in material and workmanship for a period of 90 days from date of delivery During the warranty period HP Company will at its option either repair or replace products which prove to be defective HP does not warrant that the operation of the software firmware or hardware shall be uninterrupted or error free For warranty service with the exception of warranty options this product must be returned to a service facility designated by HP Customer shall prepay shipping charges by and shall pay all duty and taxes for products returned to HP for warranty service Except for products returned to Customer from another country HP shall pay for return of products to Customer Warranty services outside the country of initial purchase are included in HP s product price oniy if Customer pays HP interna tional prices defined as destination local currency price or U S or Geneva Export price If HP is unable within
35. remote programming input With rear terminals AB and A9 shorted and A10 open local control is allowed through A5R2 Remote con 4 6 troi is allowed by connecting a programming resistance be tween A9 and A10 with A8 open 4 44 A fixed 5 12V reference voltage derived from the 15V regulated bias supply zener diode A2VR4 and resistors A2R58 A2R59 is applied to the inverting input pin 2 of A2U2 through section SZA of the MODE switch and A1R42 and A2R4 Depending upon the front panel VOLTAGE control A5R2 setting or remote programming input A2U2 provides a 0 to 10V output This output is summed at the junction of A2R6 and A2R7 with the 5 12V reference which is applied through section S2B of the MODE switch This summing action provides a variable bipolar voltage output 4 45 In the variable gain amplifier mode the 5 12V refer ence is removed and an external signal dc or ac applied to the HI IN A1 and LO IN A2 terminals is fed to the invert ing input of A2U2 For this mode the VOLTAGE control A5R2 or remote programming input controls the gain of A2U2 from O to 2X and summing with the dc references is not performed 4 46 Diodes A2CR1 and A2CR2 limit the maximum input to the A2U2 amplifier protecting it from excessive voltage excursions Variable resistors ATR1 V ZERO on front panel A2R58 course adjustment and A2R59 fine adjustment in the reference voltage circuits are used to calibrate zero output v
36. shown in Figure 5 3 two coax cables must be substituted for the shielded two wire cable b Impedance matching resistors must be included to eliminate standing waves and cable ringing and the cap acitors must be connected to block the OC current path c The length of the test leads outside the coax is critical and must be kept as short as possible the blocking capacitor and the impedance matching resistor should be connected directly from the inner conductor of the cable to the power suppiy terminals d Notice that the shields of the power supply end of the two coax cables are not connected to the power sup ply ground since such a connection would give rise to a ground current path through the coax shield resulting in an erroneous measurement e Since the impedance matching resistors consti tute a 2 to 1 attenuator the noise spikes observed on the oscilloscope should be less than X1 Range X4 Range 2mVp p instead of 7 5mV p p instead of 4mVp p 15mVp p son TERMINATION WER SUPPLY T CON R OSCILLOSCOPE ge CASE pc CASE Oluf T CONNEC TOR son TERMINATION Figure 5 3 CV Noise Spike Tast Setup 5 28 Transient Recovery Time Definition The time X for the output voltage recovery to within Y millivolts of the nominal output voltage following a Z amp step change in load current where Y is specified as 20mV the nominal output voltage is defined as the dc leve between the static output voltag
37. the fol am rear panel to 5000 3129 graphs 2 18 and 2 19 with the following 2 18 slo blow for 220 V or 240 V lowing changes Under Ah Power Module Change Ah Power Module to HP P N 0960 0444 Under assis Mechanical Change HP P N of the bot Replace para Model 6825A may be operated continuously from a nominal 100 V 120 V 220 V or 240 V 18 63 Hz power source A printed circuit board located within the ac power module on the rear panel selects the power source Voltage choices are available on both sides of the PC board Before connecting the in strument to the power source check that the PC board selection matches the nominal line voltage of the source The operating voltage is shown in the window of the ac power module If required select the proper volt age as follows refer to Figure 2 2 a Remove power cable from instrument b Move plastic door on power module aside e Rotate FUSE PULL to the left and remove line fuse Fl d Remove PC board from slot Select operating voltage by orienting PC board to position the desired voltage on top left side of PC board Push board firmly into slot e Rotate FUSE PULL back into normal position and re insert fuse F1 in holder sing caution to select the correct value for 4 1A slo blow for 100 V or 120 V and 0 5A f Close plas tic door and connect power cable P O A amp POWER MODULE i GND amp EL GRN LS AA ZS SA VOLTAGE SELECTI
38. the latter consists of all parts not immediately associated with an assembly 6 3 ORDERING INFORMATION 6 4 To order a replacement part address order or in quiry to your loca Hewlett Packard sales office see lists at rear of this manua for addresses Specify the following information for each part Model compiete serial number and any Option or special modification J numbers of the instrument Hewlett Packard part number circuit reference designator and description To order a part not listed in Table 6 4 give a complete description of the part its func tion and its location Table 6 1 Reference Designators miscellaneous electronic part fuse jack jumper relay inductor meter A assembly B 7 blower fan C 7 capacitor CB circuit breaker CR diode DS device signaling lamp 6 1 Tabie 6 1 Reference Designators Continued plug transistor resistor switch transformer B terminal block thermal switch V vacuum tube neon bulb photocell etc VR zener diode X ssocket Z X integrated cir cuit or network Table 6 2 Description Abbreviations A ampere ac alternating current assy assembly bd board bkt bracket OC degree Centigrade cd card coef coefficient comp composition CRT cathode ray tube CT center tapped dc direct current DPDT double pole doubie throw OPST doubie poie single throw ele
39. the load CURRENT SAMPLING TERMINALS TO GROUNDED TERMINAL OF POWER SUPPLY TO UNGROUNDED TERMINAL OF POWER SUPPLY SAMPLING RESISTOR LOAD TERMINALS Figure 5 9 Current Sampling Resistor Connections 5 44 For all output current measurements the current sampling resistor must be treated as a four terminal device In the manner of a meter shunt the load current is fed to the extremes of the wire leading to the resistor while the sampling terminals are located as close as possible to the resistance portion itself see Figure 5 9 Generally any current sampling resistor should be of the low noise low temperature coefficient less than 20ppm 9C type and should be used at no more than 10 6 of its rated power so that its temperature rise will be minimized NOTE The CURRENT MODE light should be on dur ing these tests 5 45 Rated Output and Meter Accuracy a Connect test setup shown in Figure 5 10 Use high range load resistor R4 connected in series with the 10 resistor Rc b Set BPS A front panel controls as follows MODE switch POWER SUPPLY RANGE switch X4 VOLTAGE control fully clockwise CURRENT control fully counterclockwise VOLTAGE METER high range DC CURRENT METER high range DC c Turn on BPS A and adjust CURRENT control until front panel ammeter indicates maximum rated positive output current d DVM should read 2 0V e Turn VOLTAGE control fully counterclock wise and adjust CURRENT
40. the power supply and the vertical input of the scope and the grounded scope case Any ground current nirculating in this loop as a result of the difference in poten tial Eg between the two ground points causes an IR drop which is in series with the scope input This IR drop norm ally having a 60H2 line frequency fundamental plus any pickup on the unshielded leads interconnecting the power supply and scope appears on the face of the CRT The magnitude of this resulting noise signal can easily be much greater than the true ripple developed between the plus and minus output terminals of the power supply and can completely invalidate the measurement 5 20 The same ground current and pickup problems can exist if an RMS voltmeter is substituted in place of the oscil loscope in Figure 5 2 However the oscilloscope display unlike the true RMS meter reading telis the observer im mediately whether the fundamental period of the signal dis played is 8 3 milliseconds 1 120Hz or 16 7 milliseconds 1 60Hz Since the fundamental ripple frequency present on the output of an HP supply is 120Hz due to full wave POWER SUPPLY CASE OSCILLOSCOPE CASE A INCORRECT METHOD GROUND CURRENT Is PRODUCES 60 CYCLE DROP iN NEGATIVE LEAD WHICH ADOS TO THE POWER SUPPLY RIPPLE DISPLAYED ON SCOPE POWER SUPPLY CASE OSCILLOSCOPE CASE USE 3 70 2 ADAPTER TO BREAK GND PATH B A CORRECT METHOD USING A SINGLE ENDED SCOPE OUTPUT FLOATED TO BREAK GROUND CU
41. 0 and A21 Apply a small variable dc voltage approxi mately 0 2Vdc between terminals A21 and A18 e Connect a DVM between A2U4 pin 6 TP17 and S Turn on power and note the DVM reads approxi mately 7V to BV as the source voltage is varied through zero If reading is not correct the A2U4 stage is defective 5 75 RMS Current Meter Driver Integrated circuit A2U5 provides the gain necessary to drive diode detector A1CR18 which allows ac current to be metered through the detection process To determine if A2US is operational apply a sinewave 2V p p 100Hz with a dc offset of 0 2 Vdc to the OUT side of A2C13 Observe that a sinewave of approximately 28 30V p p is present at pin 6 of A2U5 Connect oscilloscope between A2U5 pin 6 and U for this measurement 5 76 A3BOARD AND HEAT SINK ASSEMBLY TROUBLESHOOTING The following troubleshooting procedures are performed with power applied to the BPS A while its protective covers are re moved Be careful when performing the procedures as line voltage is always pres ent on the power input connector fuse holder and in the power supply rectifier circuits In addition when the supply is on energy available at many points par ticularly the power transistors on the rear heat sink may result in personal injury or death when contacted 5 77 The A3 plug in board contains positive and negative amplifier and driver stages which amplify the control voltage from board
42. 1 load resistance connected as shown in Figure 5 1 Set RANGE switch to X1 i Observe differential voltmeter readings Differ ence in voltage reading between step e and g should be less than B 5mV Drift Output Stability Definition The change in output voltage for the first eight hours following a 30 minute warm up period During the inter val of measurement al parameters such 5 39 5 8 as load resistance ambient temperature and input line voltage are held constant 5 40 This measurement is made by monitoring the out put of the power supply on a differential voltmeter or digi tal voltmeter over the stated measurement interval a strip chart recorder can be used to provide a permanent record A thermometer should be placed near the supply to verify that the ambient temperature remains constant during the period of measurement The supply should be put ina location immune from stray air currents open doors or windows air conditioning vents if possibie the supply should be placed in an oven which is held at a constant tem perature Care must be taken that the measuring instrument has a stability over the eight hour interval which is at least an order of magnitude better than the stability specification of the power suppiy being measured The supp y wili drift considerably less over the eight hour measurement interval than during the half hour warm up 5 41 To check the output stability proceed as follows
43. 10mV pp f Turn VOLTAGE control fully counterciock wise and repeat steps d and e for maximum rated nega tive output current tOn TERMINATION n x d OSCILLOSCOPE T CONNECTOR CASE POWER SUPPLY CASE i VERTICAL LENGTK OF LEAD BETWEEN Ry AND GROUNDED OUTPUT T CONNECTOR TERMINAL OF POWER SUPPLY son MUST BE HELD TO ABSOLUTE TERMINATION MINIMUM Figure 5 12 Constant Current Noise Spike Test Setup 5 52 Noise Spike Measurement To check the noise spike output proceed as follows a Connect test setup shown in Figure 5 12 b Turn VOLTAGE control fully clockwise c Set RANGE switch to X4 MODE switch to POWER SUPPLY and turn on BPS A d Adjust CURRENT control until front panel ammeter indicates the exact maximum rated positive output Current e Since the impedance matching resistors consti tute a 2 1 divider the observed noise spikes should be less than 5mV p p 5 53 Current Sink Test The current sink test is per formed using two BPS A s One is used as a test instrument and the other is used as a source instrument Two identical BPS A s are preferred to perform this test CAUTION If two BPS A s of the same model are not avail able this test can be performed utilizing anv other Bipolar supply However it is of the utmost importance that the BPS A output voft age be set below the other supply so that it will sink rather than force the other supply to sink which it may not be capable of
44. 1100 Knob RANGE select 1 0370 1125 Clip 4 1400 0532 Retainer Ring 4 1400 0540 Lamp Holder Clear 1 5040 0234 Lamp Holder Black 1 5040 0305 Binding Post Red 4 1510 0094 Binding Post Black 1 1510 0522 Tilt Stand 1 1490 0032 Chassis Mechanical Cover Top 5000 3090 Cover Bottom 5000 9368 Cover Side 5000 9432 Chassis 5000 9364 Rear Panel Bottom 5000 9345 5080 0728 0360 0523 0380 0849 5000 9356 5080 0703 Foot Assembly Jumper Barrier Strip Standoff 8 32 x 875 Cover Barrier Strip 6 x 11 Frame Assembly Miscellaneous Fuse 5A 250V Sto Blo Power Card Packing Carton 9211 1196 Floater Pad Carton 9220 1409 Option 007 10 Turn VOLTAGE Contro var ww 20K 596 2W Unear 10 turn 28480 2100 1867 2110 0202 8120 1348 SECTION VH CIRCUIT DIAGRAMS 7 1 INTRODUCTION 7 2 This section contains the circuit diagrams necessary for the operation and maintenance of BPS A Mode 6825A 7 3 SIMPLIFIED SCHEMATIC DIAGRAM 7 4 This diagram Figure 7 2 shows the relationship be tween the instrument assemblies and ties the schematic dia gram sheets together 7 5 COMPONENT LOCATION ILLUSTRATIONS 7 6 The component location diagrams show the physical location of parts mounted on each assembly They are in 71 cluded on the schematic diagrams where they apply or on the rear of the previous schematic Thus the schematic diagram is unfolde
45. 15kHz e Set MODE switch to FXD GAIN AMP and re peat steps c and d above Frequency should not be less than 35kHz 5 59 Distortion Test To check the total harmonic dis tortion THD in the amplifier output proceed as follows a Connect the test setup as shown in Figure 5 16 b Set MODE switch to VAR GAIN AMP c Set generator at 100Hz sinewave and adjust out put for full BPS A output voltage and current with appro priate load d Measure the distortion at the output using HP 331A Distortion Analyzer e The THD should be less than 1 NOTE The above is a difficult measurement because the THD is so low Most audio generators will con tain more than 1 THD in their output A first order figure can be obtained by the following re lationship 5 61 GENERAL 5 62 Before attempting to troubleshoot this instrument ensure that the fault is with the instrument and not with an associated circuit The performance test Paragraph 5 5 en ables this to be determined without removing the instru ment s covers A good understanding of the principles of op eration is a helpful aid in troubleshooting and it is recom mended that the reader review Section IV of the manual be fore attempting to troubleshoot the instrument Once the principles of operation are understood refer to the trouble isolation procedures 5 63 Figure 7 1 is a simplified schematic of the BPS A and is useful in tracing signal flow through the entire ins
46. 2 5060 0796 Cooling kit for above combining case 230 Vac 50 60Hz 1 4 1 19 1 18 INSTRUMENT IDENTIFICATION Hewiett Packard power supplies are identified by a three part serial number The first part is the power supply model number The second part is the serial number prefix consisting of a number letter combination denoting the date of a significant design change and the country of manufac ture The first two digits indicate the year 12 1972 13 1973 20 1980 etc the second two digits indicate the week 01 through 52 and the letter A G J or U designates the U S A West Germany Japan or the United Kingdom respectively as the country of manufacture The third part is the power supply serial number a different 5 digit sequential number is assigned to each power supply starting with 00101 1 20 Hf the serial number prefix on your unit does not agree with the prefix on the title page of this manual change sheets supplied with the manual or manual backdating changes in Appendix A define the differences between your instrument and the instrument described by this manual 1 21 ORDERING ADDITIONAL MANUALS 1 22 One manual is shipped with each instrument Add itional manuals may be purchased from your local Hewlett Packard field office see list at rear of this manual for add resses Specify the model number serial number prefix and HP part number shown on the title page SECTION II INSTALLATION
47. 2100 0741 0757 1093 0757 0123 2100 0741 0757 1093 0698 4121 0698 4428 2100 1771 0698 4428 2100 1771 0698 3150 0757 0401 0698 5541 0698 5087 0686 4325 Table 6 4 Replaceable Parts MFR HP SCRIPTI A1R26 fxd comp 7 5K 5 AW EB 7525 0686 7525 fxd comp 750 5 GW EB 7515 0686 7515 fxd comp 1K 5 4W EB 1025 0686 1025 fxd film 3 92K 1 1 8W CEA T 0 0757 0435 fxd film 6 81K 1 1 8W CEA T 0 0757 0439 fxd comp 7 5K 5 VW EB 7525 0686 7525 fxd film 1 3K 1 W CCA T 0 0757 0735 Not Assigned fxd film 5 49K 1 1 8W Not Assigned CEA TO 0698 3382 fxd film 9 09K 1 1 8W CEA T 0 0757 0288 fxd comp 620 5 GW EB 6215 0686 6215 fxd ww 400 5 5W A 243E 0811 1857 fxd ww 500 5 5W 243E 0811 1858 Not Assigned fxd film 10K 1 1 8W CEA T 0 0757 0442 fxd ww 10 24K 05 4W 132F 0811 2958 fxd comp 1 3K 5 AW EB 1325 0686 1325 fxd film 21 5 1 1 8W CEA T 0 0698 3430 Not Assigned fxd film 42 2K 196 1 8W CEA T 0 0698 3450 fxd film 160K 1 1 8W CEA T 0 0698 5092 fxd film 42 2 1 1 8W CEA T 0 0757 0316 Thermistor 64 1096 LB16J1 0837 0023 fxd fiim 3 16K 1 1 8W CEA T 0 0757 0279 Not Assigned fxd film 1K 1 1 8W CEA T 0 0757 0280 Not Assigned fxd ww 1 5 3W 242E 1R05 0871 1732 Not Assigned
48. 25 0686 1035 0686 5125 0686 1525 0686 5125 0686 5625 0686 1015 0686 4325 0686 1625 0686 1835 0686 6205 0686 2015 Table 6 4 Replaceable Parts REF HP PART NO A3R31 fxd comp 10K 5 AW EB 1035 0686 1035 R32 fxd comp 30 5 GAN EB 3005 0686 3005 R33 fxd comp TOK 5 AW E8 1035 0686 1035 R34 fxd comp 30 5 W EB 3005 0686 3005 R35 36 fxd comp 330 5 4W EB 3315 0686 3315 R37 42 fxd comp 39 5 4W EB 3905 0686 3905 R43 44 fxd comp 360 5 AN EB 3615 0686 3615 R45 48 fxd ww 1 5 5W 243E 0811 1340 R49 Not Assigned R50 51 fxd ww 1 5 5W 243E 0871 1340 R52 Not Assigned R53 fxd comp 30 5 4W EB 3005 0686 3005 R54 fxd comp 47 5 4W EB 4705 0686 4705 R55 fxd comp 10 596 W EB 1005 0686 1005 R56 65 Not Assigned R66 fxd comp 160K 5 W EB 1645 0686 1645 Diode zener 28 7Vdc SZ11213 272 1902 0572 Power Module inctudes slide switch and fuse Fuse 1A 250V Slo Blo 5060 1189 2110 0007 Front Panel Electrical DS1 Indicator Lamp LINE 2140 0037 DS2 indicator Light Emitting Diode CURRENT MODE 1990 0325 M1 Voltmeter Dual Range DC or AC 22 4 24Vdc or 1 6 16V rms 1120 1371 M2 Ammeter Dual Range DC or AC 20 24 2 4A or 0 16 1 6A rms 1120 1379 R1 var ww dual ganged 15K 15K CURRENT Control 2100 3271 R2 var
49. 39 146 S210939 146 LM301AH 0686 8205 0757 0438 0811 2958 0757 1093 0757 0440 0698 5087 0757 0438 0757 0446 0686 1025 0698 3476 0757 0401 0698 3476 0757 0452 0757 0283 0757 0440 2100 1758 2100 1752 2100 1755 0698 3153 0698 0084 0698 3153 0698 0084 0757 0280 0757 0439 0757 0280 0698 3382 0757 0451 0757 0431 0757 0451 0757 0283 3101 1311 1902 1221 1902 0064 1902 0064 1820 0223 Power Amplifier Plug In Board fxd elect 20uF 15Vdc fxd elect iuF 35Vdc Not Assigned 06825 60022 0180 0300 0180 0291 30D 206G0168B2 DSM 150D 105X9035A2 fxd cer 22uF 50Vdc 1 5C52B CML 0160 0263 1 fxd cer O2uF 500Vdc 2 C0238501J2032825 0160 0468 1 fxd mica 150pF 300Vde 1 RDM15F 151J3C 0140 0196 1 fxd mica 470pF 500Vde t 0140 0149 1 fxd mylar 001uF 200Vdc 1 192P 10292 0160 0153 1 6 8 ig 41 A3C12 13 C14 C15 CR1 7 CRB 13 CR14 CR15 17 CR18 CR19 21 CR22 Q1 02 Q3 Q4 5 DESCRIPTION fxd mylar 047uF 200Vdc fxd cer Q2uF 500Vdc fxd cer 5000pF 1KV Diode Si 200mA 75V Not Assigned Stabistor Si 10prv 400mW Diode Si 200mA 75V Not Assigned Diode Si 200mA 75V Diode Hot Carrier SS NPN Si SS NPN Si SS PNP Si SS NPN Si SS PNP Si SS NPN Si SS PNP Si SS NPN Si SS PNP Si SS NPN Si SS PNP Si fxd comp 15K 5 AW fxd co
50. 40kHz Total harmonic distortion is 0 196 maximum 1 10 METERS 1 11 A voltmeter and an ammeter on the front panel monitor the ac or de output voltage and current respective ly Associated front panel VOLTAGE METER and CUR RENT METER switches allow the meters to monitor either an ac or dc output and also provide dual range monitoring capability for better resolution The dc meter accuracy is 3 of full scale and the ac meter accuracy is 1596 of full scale l 1 12 SPECIFICATIONS 1 13 Detailed specifications for this mode are given in Table 1 1 Table 1 1 Specifications Model 6825A GENERAL SPECIFICATIONS input Power 104 127 208 254Vac switchabie 48 63Hz 1 0A 150W Meters Individual voltage and current meters DC accuracy is 3 of full scale AC accuracy is 5 of full scale with sinusoidal 100Hz input Meter Ranges DC 2 4V 24V 0 24A 2 4A Meter Ranges AC 1 6V uncal 16V rms 0 16A rms 1 6A rms Temperature Ratings Operating 0 to 55 C Storage 40 to 75 C Cooling Convection cooling is employed The supplies have no moving parts Dimensions See outline diagram Figure 2 1 Weight 18 ibs 8 2 kg net 21 Ibs 9 5 kg shipping POWER SUPPLY SPECIFICATIONS DC Output Voltage and current spans indicate range over which output may be varied j X1 Range 5V to BV O to 20A X4 Range 20V to 20V O to 2 0
51. 5 t BVde A1CS C6 C8 CR10 CR11 A1C13 C14 C16 CR16 CR17 A1C3 C17 CR3 CRS CRE Q1 02 VR1 A1C4 C18 CR7 CRB Q3 04 VR3 TP7 20 2Vdc unfil A1CR1 CR2 TP8 Reference Voltages 20 2Vde fil A1CRS CR6 C3 6 2 35Vdc A2VR4 B 2 t 35Vdc A2VR3 36 2 38V dc i A2VR2 6 2 t 35Vdc A2VR1 NOTE Test points 1 through 8 are shown on sheet 1 and test points 9 through 12 are shown on sheet 2 of schematic All voltages specified at nomina line 5 15 5 68 Overall Trouble isolation Guide After checking output voltage gain The voltage control stages A2U1 and the supply voltages disconnect the load and examine Table A2U2 are common to both positive and negative outputs 5 3 This table contains a list of symptons and probable The bipolar amplifier circuits on board A3 and the bipolar causes that may cut down on troubleshooting time For series regulator output amplifier stages on the heat sink each trouble symptom Table 5 3 isolates the trouble to a assembly consist of positive and negative stages for positive component or group of components or directs the reader to and negative outputs respectively The current control cir additional procedures if further isolation of the trouble is cuits consist of positive current comparison stage A2U3 necessary and negative current comparison stage A2U4 and associ ated common circuits consisting of dua ganged CURRENT control A5R1 speedup network A2Q1 C9
52. 59 0757 0288 0698 5088 0757 0283 0757 0441 0757 3430 0757 0441 A2R40 fxd comp 82 5 W R41 fxd film 5 11K 1 1 8W fxd ww 10 24K 05 4W Not Assigned fxd film 3K 1 1 8W fxd film 7 5K 1 1 8W fxd film 6 2K 1 1 8W fxd film 5 11K 1 1 8W fxd film 15K 1 1 8W fxd comp 1K 5 W fxd film 6K 1 1 8W fxd film 100 1 1 8W fxd film 6K 1 1 8W fxd film 27 4K 196 1 8W fxd film 2K 195 1 8W fxd film 7 5K 1 1 8W var ww 1K 5 1W var ww 10 5 TW vat ww 100 5 1W Not Assigned fxd film 3 83K 1 1 8W fxd film 2 15K 1 1 8W fxd film 3 83K 196 1 8W fxd film 2 15K 1 1 8W Not Assigned fxd film 1K 1 1 8W fxd film 6 81K 1 1 8W fxd film 1K 1 1 8W fxd film 5 49K 1 1 8W fxd film 24 3K 1 1 8W fxd film 2 43K 1 1 8W fxd film 24 3K 1 1 8W fxd film 2K 1 1 8W Diode zener 6 2V Diode zener 7 50V 400mW Not Assigned Diode zener 7 50V 400mW IC Linear Amplifier Slide Switch 0 5A 125Vac dc Tabie 6 4 Replaceable Parts HP sh DESCRIPTION i MEE EB 8205 CEA TO 132F CEA T 0 CEA T 0 CEA T 0 CEA T 0 CEA T 0 EB 1025 CEA T 0 CEA T 0 CEA T 0 CEA TO CEA T 0 CEA T 0 CT 106 4 CT 106 4 CT 106 4 CEA T 0 CEA TO CEA T 0 CEA T 0 CEA T 0 CEA T 0 CEA T 0 CEA T 0 CEA T 0 CEA TO CEA T 0 CEA T 0 GF 126 0020 1N825 2109
53. 9 Model 6825A Page 5 CHANGE 11 In the replaceable parts list page 6 10 un der A5 Front Panel Electrical delete R2 var ww 25 k 5 2 W HP P N 2100 3272 and add 5 var ww 20k 51 2 M qty 1 Also on dge 6 11 under Front Panel Mechanical delete Knob pointer HP P N 0340 1090 qty 1 and add HP P N 0370 1091 qty 1 On page 6 6 delete R53 HP P N 0698 5092 This change obsoletes Option 009 CHANGE 12 On page 1 2 Table 1 1 ehange the Resolution Spec for Voltage X1 Range to 4mv and X4 Range to i mv CHANGE 13 In the replaceable parts list page 6 10 below 31 add HP P N 5001 6715 polimide paper insulator qty 1 The insulator is in stalled over 1 CHANGE 14 This change is retroactive starting with prefix serial number 2312A 01001 01110 see table on page 1 of this change page On page 1 3 Table the Remote Resistance 4 shown below wami mcr fm eff ien t HEUK i 5 OE A A tei L 1 1 Speefieations Grange ao Drag 4 AE Vy Resistanoe Coefficient Voltage X1 Range 20000hms V typical Voltage X4 Range 500ohms V typical On page 5 23 add the following NOTE and steps to paragraph 5 104 This procedure steps a through should be followed to achieve optimum accuracy when programming with an external resistance This procedure may not allow full scale voltage adjustment when using the front panel VOLTAGE control 10 turn potentiometer A2R5 on units wit
54. A Load Effect Load Regulation Voltage load effect is given for a load current change equal to the current rating of the supply Current load effect is given for a load voltage change equal to the voltage rating of the supply Voltage X1 Range 0 01 ImV Voltage X4 Range 0 01 5mV Current 01 250uA Source Effect Line Regulation For a change in line voltage between 104 and 127Vac 208 and 254Vac at any output voltage and current within rating Source Effect Line Regulation Continued Voltage X1 Range 01 2mV Voltage X4 Range 01 2mV Current 01 250uA PARD Ripple and Noise Rms p p 20Hz to 20MHz at any line voltage and un der any load condition within rating Voltage X1 Range 1 5mV rms 4mV p p Voltage X4 Range 5mV rms 15mV p p Current 3mA rms 10mA p p 4 Temperature Coefficient Output change per degree Centigrade change in am bient following 30 minutes warm up Voltage X1 Range 01 35mV Voltage X4 Range 01 1 5mV Current 02 100uA Drift Stability Change in output dc to 20Hz over 8 hour interval under constant line load and ambient following 30 minutes warm up Voltage X1 Range 03 1mV Pot wiper jump effect may add 5mV O396 5mV Pot wiper jum ipi effect may add 50mV 1 200uA Pot wiper jump effect may add 1 5mA Voltage X4 Range Current Load Effect Transient Recovery Load Transient Recovery Time required for outpu
55. ADJ potentiometer as described in Paragraph 5 104 The output voltage varies from the maximum negative value to the maximum positive value through O at a rate deter mined by the resistance programming coefficient as follows High range X4 500ohms volt 1 Low range X1 2000ohms volt 1 CAUTION When remote control programming is employed the FLAG A17 and REMOTE RANGE ATT programming connections must be isolated from the computer ground 3 45 The switch connected between the A11 and S terminals allows remote selection of the high X4 or low X1 range Note that the front panel RANGE switch must be in the REMOTE position in order to utilize the remote selection feature The remote dc control voltage connect ions between terminals A15 and A16 activate an internal relay When the control voltage is applied the interna re lay is energized momentarily disabling the input driver to the BPS A error amplifier This feature is used to prevent transients from affecting the output when the programming input is changed Terminal A17 provides an indication to the external programming device when the BPS A is in con stant current operation 3 46 Variable Gain Amplifier For variable gain amplifier operation an external input signal dc to 15kHz applied to terminals A1 H1 IN and A2 LO IN is amplified or atten uated The gain is variable from 0 to a maximum value as the value of Rpy varies from 0 to 20 48K ohms Th
56. Auto switch in the Auto position The diagrams show the master strapped for local programming and with an external signal applied to the amplifier input terminals However the same auto series or auto parallel connections could be used with the master strapped for remote programming Also with the master supply in the power supply mode the external signal applied to the Al and A terminals is internally disconnected POWER SUPPLY OR VARIABLE GAIN AMPLIFIER MODE LOCAL AUTO SWITCH itt LOCAL AB A9 AIO Ali l A 3 Al eg GEEEEER GZ AB AG AI AIS AID AZO AZ ejejejejerg p SLAVE t FIXED GAIN AMPL MODE LOCAL AUTO SWITCH IN AUTO AS AS AIO A AI Am Als eiglelelalgle R Z ap AIG AIT AIB AIS A2D A21 eje ejejejqel SLAVE 2 FIXED GAIN AMPL MODE LOCAL AUTO SWITCH IN AUTO A8 A8 AIO Al AI2 AIS Als 1 ele elol J GZ AtS AiG AI AB AID A20 A3 EEEGEER Figure 3 12 Auto Series Connections Three Units 3 10 3 59 Auto Series Operation Two or more BPS A s can be connected in an auto series arrangement to obtain a high er output voltage than that available from a single supply Figure 3 12 illustrates the auto series connections for three supplies When this arrangement is used the output voltage of each slave supply varies in accordance with that of the master supply thus the total output voltage of the combin ation is determined by the master supply s front panel VOLTAGE contro
57. Co Mt Kisco N Y Mepco Morristown N J Bourns Inc Riverside Calif Howard Industries Racine Wisc Grayhill Inc La Grange lil International Rectifier EI Segundo Calif Columbus Electronics Yonkers N Y Goodyear Sundries amp Mechanical Co Inc New York N Y Airco Speer Electronic Components Du Bois Pa Sylvania Electric Products Inc Emporium Pa Switchcraft Inc Chicago lil Metals and Controls Inc Attleboro Mass Use Code 71785 assigned to Cinch Mfg Co Chicago Ill 6 4 CODE MANUFACTURER ADDRESS 82866 Research Products Corp Madison Wise Rotron Inc Woodstock N Y Vector Electronic Co Giendale Calif Carr Fastener Co Cambridge Mass Victory Engineering Springfield N J Bendix Corp Eatontown N J Herman H Smith inc Brooklyn N Y Centra Screw Co Chicago Il Gavitt Wire and Cable Brookfield Mass Grant Pulley and Hardware Co West Nyack N Y Burroughs Corp Plainfield N J U S Radium Corp Morristown N J Yardeny Laboratories New York N Y Arco Electronics inc Great Neck N Y TRW Capacitor Div Ogallala Neb RCA Corp Harrison N J Rummet Fibre Co Newark N J Marco amp Oak industries Anaheim Calif Philco Corp Lansdale Pa Stockwell Rubber Co Philadelphia Pa Tower Olschan Corp Bridgeport Conn Cutler Hammer inc Lincoln Hi Litton Precision Products inc USECO Van Nuys Calif Guiton Industries Inc Metu
58. E switch ei allows the BPS A to oper ate as a power supply variable gain amplifier or a fixed gain amplifier In power supply operation the BPS A provides a variable bipolar dc output voltage dependent upon the RANGE switch A and VOLTAGE control 5 set tings The dc output voltage ranges are as follows BV to 5V low range and 20V to 20V high range ER GE27A BIPOLAR POWER SUPPLY ZAMPLIFIER 5 Plvimieyt waceara LEM gm ZERG AD Figure 3 2 Operating Controls and Indicators Typical BPS A 3 8 in variable gain amplifier operation the BPS A can amplify or attenuate an external input signal dc to 15kHz applied to the HI and LO IN terminals The gain is variable from 0 to a maximum depending upon the RA GE switch and VOLTAGE control B settings The variable gain ranges are as follows 0 2 low range and 0 8 high range 3 9 In fixed gain amplifier operation the BPS A inverts and amplifies an external input signal applied to the HI and LO IN terminals For fixed gain amplifier operation the BPS A has a frequency response from DC to 40kHz The fixed voltage gain provided in the high or low output range is as follows times 1 low range and times 4 high range 3 10 RANGE SWITCH 3 11 The RANGE switch 4 allows selection of the high X4 or low X1 output ranges for power supply variable gain amplifier or fixed gain amplifier operation The REMOTE position allows the high or low range to be ex
59. Negative constant current cir NPN switch A2Q6 opened cuits operate properly but CURRENT MODE indicator does not light CURRENT MODE indicator always on FLAG output low FLAG output terminal A17 FLAG driver A204 opened always high about 16V CURRENT MODE indicator Diode A2CR10 opened always on and FLAG output always high Defective lamp driver circuit A202 opened or A2Q3 shorted Constant current circuits operate a Indicator LED ABDS2 defective normally but CURRENT MODE b Defective lamp driver circuit A2Q2 shorted or A2Q3 opened indicator does not light 5 17 Table 5 3 Overall Trouble Isolation Guide Continued SYMPTOM Constant current circuits operate normally but no FLAG output always tow PROBABLE CAUSE a FLAG driver A204 shorted b Jumper A2W1 not installed A2CR3 CR11 CR12 or R28 defective A2CR4 CR7 CR8 or R29 defective tive Bandwidth too narrow in VAR GAIN AMP mode A2U1 defective 5 70 cedure describes how to isolate trouble to the turn on off circuit on boards A1 and A3 the voltage current contro circuits on board A2 or to the output power amplifier stages on board A3 and the heat sink assembly The board isolation procedures assumes that an output problem exists in all three modes of operation and al trouble isolation pro cedures up to this point have been completed To isolate the trouble to the defective board s proceed as follows
60. ON Operating Voitage is shown ln module window VOLTAGE SELECT PC BOARD FUSE PULL Figure 2 2 Line Voltage Selection 2 19 When the instrument leaves the factory a lA fuse is installed for 120 V operation An envelope containing a 0 5 A fuse for 220 V 2B80 V operation is attached to the instru ment Make sure that the correct fuse value for Fl is installed if the position of the PC board is changed Change the schematic Figure 7 2 Sheet 1 to illustrate the new Ah Power Module 0960 0444 as shown below Add the following to the Ordering Additional Manuals paragraph in Section I Extra man muals may be obtained by specifying Option 910 when ordering your instrument The number of extra manuals depends upon the quantity of Option 910 s ordered P O A4 POWER MODULE H 1 SAFETY GND SELECT OPERATING VOLTAGE BY ORIENTING BOARD TO POSITION THE DESIRED VOLTAGE ON TOP LEFT SIDE OF P C BO AND PUSHING BOARO FIRMLY INTO POWER MODULE SLOT e am ne ong ERRATA When using a programmable resistance card in stalled in a 6940B Multiprogrammer to program the PS A it is possible to generate spikes at the PS A s output unless its output is held at the former value until a new value has been programmed An internal relay operated by a control voltage applied between terminals A15 and A16 disconnects the input to the voltage comparison amplifier and momentarily opens its dc feedback
61. REPAIR COMPLETED ADJUSTMENT AND CALIBRATION PARAGRAPH 5 98 PERFORMANCE TEST PARAGRAPH 5 5 Figure 5 17 Trouble isolation and Troubleshooting Procedure Overall Scheme 2 Ensure that the MODE and RANGE switches proper rating 1A for 115Vac or 0 5A are in the desired position for 230Vac 3 Check the line fuse If the line fuse is open proceed as follows b Check the following a Ensure that the proper ac input 115 l On chassis check for short circuits Main or 230Vac is selected slide switch on power transformer T1 and filter capaci power module and install a fuse of tors C1 C2 and C3 5 14 On board AT check for short circuits Al filter capacitors and rectifier diodes Also check for shorts across power tracks on board On board A3 check for short or open cir cuits A3C11 Q12 Q 19 shorted A3CR14 CR17 opened On heat sink assembly Check output power transistors 4 Check that the LOCAL AUTO switch on board A2 is in the LOCAL position see Figure 3 9 For normal operation of the BPS A this switch must be left in the LOCAL position The AUTO position is used only for auto series auto parailel operation see Section IH 5 Check continuity of ribbon cables W1 and W2 from the A1 board to the heat sink assembly and rear term inal strips respectively 6 Check for defective meter s power cord and loosely connected circuit boards Visually inspect circuit boards for mechanical damage and disco
62. RRENT LOOP TWISTED PAIR REDUCES STRAY PICKUP ON SCOPE LEADS POWER SUPPLY CASE OSCILLOSCOPE CASE C A CORRECT METHOD USING A DIFFERENTIAL SCOPE WITH FLOATING INPUT GROUND CURRENT PATH IS BROKEN COMMON MODE REJECTION OF DIFFERENTIAL INPUT SCOPE IGNORES DIFFERENCE IN GROUND POTENTIAL OF POWER SUPPLY A SCOPE SHIELDED TWO WIRE FURTHER REDUCES STRAY PICK UP ON SCOPE LEADS HI RANGE LO RANGE 0 j 25 Figure 5 2 Ripple and Noise Test Setup rectification an oscilloscope display showing a 120Hz fundamental component is indicative of a clean measure ment setup while the presence of a 50Hz fundamental usu ally means that an improved setup will result in a more ac curate and lower value of measured ripple 5 21 Figure 5 2B shows a correct method of measuring the output ripple of a constant voltage power supply using a single ended scope The ground loop path is broken by floating the power supply Note that to ensure that no potential difference exists between the supply and the oscil loscope it is recommended that whenever possible they both be plugged into the same ac power buss 1f the same buss cannot be used both ac grounds must be at earth ground potential 5 22 Either a twisted pair or preferably a shielded two wire cable shouid be used to connect the output terminals of the power supply to the vertical input terminals of the scope When using a twisted pair care must be taken that one of the two wires
63. a DVM reading of 1h 40 6 V rms c Adjust A1R18 for a 1NA rms on front panel ammeter In the Replaceable Parts Table and on the schematic make the following changes Under A2 voltage and current control plug in board Delete CR5 diode HP P N 1901 0050 VR5 zener diode HP P N 1902 1221 VR6 zener diode HP P N 1902 006h Change C7 to fxd 4300pF 500 V HP P N 0160 2036 Under Al Interconnect and Power Supply Board Change R9 to fxd film 2 15 k 1 1 8 W HP P N 0698 0084 R10 to fxd film 3 32 k 1 1 8 W HP P N 0757 0h33 R11 to fxd film 36 5 k 1 1 8 W HP P N 0757 0455 Rik to fxd film 1 k 15 1 8 W HP P N 0757 0280 R15 to fxd film 178 15 1 8 W HP P N 0698 3539 R16 to fxd film 9 k 1 1 8 W HP P N 0698 5454 R17 to fxd film 825 14 1 8 W HP P N 0757 0421 R19 to fxd film 900 415 1 8 W HP P N 0757 1099 R21 to fxd film 2 15 k 1 1 8 W HP P N 0698 0084 Change steps g and b Adjust mica Hee to fxd film 34 0 3 1 8 W HP 9 N 0698 3434 R23 to fxd film 499 14 1 8 W HP P N 0698 4123 R24 to fxd film 6 k 15 1 1 8 W HP P N 0698 3476 R58 to fxd film 750 1 1 8 W HP P N 0757 0420 M On Sheet 1 of Figure 7 2 Connect resisvor A1R15 178 ohms 1 8 W between A1S1C pin 12 and AlS1B pin 4 CHANGE 2 This change improves transient response by eliminating oscillations in the CV CC cross over region In the Replaceable Parts Table and on the Vo
64. and A2U4 respec tively These networks in conjunction with local compen sation represented by A2C9 R46 and R47 common to both A2U3 and A2U4 provide response Stabilizing com pensation 4 55 if the output current increases above the set value the input to pin 3 of A2U3 becomes less positive For this condition the output pin 6 of A2U3 goes negative forward biasing A2CR14 With A2CR14 forward biased the BPS A switches from constant voltage to constant current operation and an error signal is applied to alter the series regulator positive conduction and maintain the output current at the desired value Also for this condition A2QB is switched on back biasing diodes A2CR9 and A2CR10 With A2CR9 back biased A2Q1 is turned off With A2CR10 back biased the CURRENT MODE indicator DS1 lights A2Q2 off A2Q3 on and the FLAG output is enabled A204 turned off providing a high FLAG output 4 56 During current sinking operations the input to A2U3 negative voltage case is altered causing the current being sinked to increase or decrease in response to the volt age magnitude of the active load When the output voltage is negative diodes A2CR3 and A2CR12 become forward biased through A2R28 altering the reference current to A2U3 This condition in conjunction with the voltage change across A2R27 will cause the output of A2U3 to adjust the drive to the appropriate output transistors to limit the imposed load current The operation of A2UA
65. and note that maximum voltage is attained as indicated on meter 3 22 OPERATING MODES CAUTION Rear terminal strip cover must be in place when instrument is in use 323 The position of the front panel MODE switch de terrnines whether the instrument will be used as a power supply or an amplifier in addition the instrument may be controlled locally using the front pane VOLTAGE and CURRENT controls or remotely via terminals on the rear of the unit The front pane output terminals HI and LO OUT and input terminals Hl and LO IN are repeated as and and A1 and A2 respectively on the rear termin al strip The rear terminal strip includes sensing 5 and S terminals and other terminals for remote control of the BPS A as shown in Figure 3 3 These terminals connect to various control points within the instrument and allow SENSE TERMINALS SIGNAL INPUT TERMINALS pzm init OJ OUTPUT TERMINALS LO BI Al A2 s 3 t 2 22 2 2 2 2 REMOTE RANGE i CONTROL CONSTANT VOLTAGE PROGRAMMING Lesen AB AD AIO Ai AG AIS Ald EE CONSTANT CURRENT FLAG QuTPuT PROGRAM INTERRUPT 7 CONSTANT RELAY CONTROL CURRENT PROGRAMMING ITEM A AIG AI AE AS AZO AZI eee CONSTANT Figure 3 3 Rear Terminal Strip strapping connections to be made which enable the power supply or amplifier to be utilized in many applications The following paragraphs describe the procedures for utilizing t
66. are referenced to GJ common Transistor Q8 in the emitter circuit of coupling amplifier Q7 serves to minimize unwanted ground current from flowing in the low output sense terminal The negative going output of coup ling amplifier stage Q7 is applied to voltage amplifier Q6 The positive Q6 08 and negative O9 O11 coupling amplifiers provide a combined gain of approximately 36X Each section positive and negative provides a gain of approximately 18X As a result of the voltage amplification the voltage across R28 biases the positive NPN driver transistors Q12 Q14 through Q16 into conduction provided that a turn on con dition is present see Paragraph 4 35 The positive driver transistors drive the positive series regulator output ampli fier transistors Q1 and Q2 These transistors are connected in series with the 35V supply voltage and thus control the BPS A output Capacitors C9 C10 and resistor R27 form networks which in addition to capacitor C11 connected be tween the HI and LO output terminals help to shape and stabilize the BPS A output response Additional local stabil ization is afforded by network C14 R53 in the positive driver circuits and network C15 R55 in the negative driver circuit 4 32 The negative section of the power amplifier operates in the same manner as that described above except that it is activated by negative going error signals and provides negative BPS A outputs The negative section is comp
67. astrophic than those previously described in that generally they lead to degraded performance rather than complete failure Table 4 Degraded Performance Problems SYMPTOM PROBABLE CAUSE Bias and reference supply Check A101 O4 A1 VRI A2VR3 A2VR4 Poor constant voltage line regulation Poor constant current line regulation Poor constant voltage load regulation Bias and reference supply Check A101 Q4 A1TVR1 A2VR1 A2VR2 Constant current operation taking place Check setting of CURRENT control A2U1 A2U2 defective Check measurement technique Poor constant current load regulation CURRENT control set too iow A2U3 A2UA defective Check measurement technique High ripple Ground loop through test equipment check test setup Excessive ripple in reference voltages Check reference voltages Table 5 2 Supply crossing over into constant current operation check setting of CURRENT control may be set too close to crossover point Defective rectifier circuits half wave instead of full wave rectification Excessive distortion in amplifier modes Supply crossing over into constant current operation Check setting of CURRENT control Defective component in amplifier circuit Check A3CR14 CR17 R29 R30 5 84 REPAIR AND REPLACEMENT 5 85 Section VI of this manual contains a list of replace able parts Tabie 5 5 contains replacement data for the semi conductors us
68. ated on DVM K Adjust variable auto transformer for a 127 Vac input 1 Reading on DVM should not vary from reading in step j by more than 4mV m Turn off BPS A and change load resistor to low range X1 value and RANGE switch to X1 n Adjust variable auto transformer for a 104Vac input o Turn on BPS A and adjust VOLTAGE control clockwise for the maximum rated positive output voltage low range as indicated on DVM p Adjust variable auto transformer for a 127Vac input q Reading on DVM should not vary from reading in step o by more than mV r Set variable auto transformer for a 104 Vac in put s Adjust VOLTAGE control counterclockwise for maximum rated negative low range output voltage as indicated on DVM t Adjust variable auto transformer for a 127Vac input u Reading on DVM should not vary from reading in step s by more than mV 5 13 Load Effect Load Regulation Definition The change A Egyr in the 5 3 static value of de output voltage resulting from a change in load resistance from open circuit to a value which yields maximum rated output current or vice versa NOTE The CURRENT MODE light should be off dur ing this test 5 14 The load regulation check is performed at low line conditions To check load regulation proceed as follows a Connect the test setup shown in Figure 5 1 Use the high range X4 load resistance value b Connect variable auto transformer between the inp
69. ating the instrument from a two contact outlet use a three prong to two prong adapter and connect the green lead on the adapter to ground SECTION IH OPERATING INSTRUCTIONS ROM POWER MODULE M kC CZEK CZE Figure 3 1 Bipolar Power Supply Amplifier Rear View 3 1 INTRODUCTION 32 This section describes the operating controls and indicators the turn on checkout sequence and operating modes of the Bipolar Power Supply Amplifier BPS A Local and remote programming operations are also des cribed 3 3 REAR TERMINALS AND AC INPUT 3 4 The Bipolar Power Supply Amplifier BPS A is shipped with the rear terminals strapped for local program ming using front panel controls as shown in Figure 3 1 Remote programming strapping requirements are described in subsequent paragraphs The power module contains fuse F1 2A for 115Vac or 1A for 230 Vac and a slide switch for connecting 115Vac or 230Vac input power to the instru ment To turn on the BPS A set the LINE switch item 1 Figure 3 2 to ON The LINE ON indicator 3 1 should light Fuse F1 protects the main power supply At initial turn on an internal circuit protects any loads con nected to the BPS A from turn on transients by shorting the output terminals and disabling the BPS A s power out put circuits This circuit operates similarly at turn off to protect any loads from turn off transients 3 5 OPERATING CONTROLS AND INDICATORS 3 5 MODE SWITCH 37 The MOD
70. chen N J United Car inc Chicago Ill Miller Dial and Nameplate Co El Monte Calif Radio Materials Co Chicago ili Augat Inc Attleboro Mass Dale Electronics Inc Columbus Neb Eico Corp Willow Grove Pa Honeywell Inc Freeport IIl Whitso Inc Schiller Pk Hi Sylvania Electric Prod Woburn Mass Essex Wire Corp Mansfield Ohio Raytheon Co Quincy Mass Wagner Electric Corp Livingston N J Southco inc Lester Pa Leecraft Mfg Co inc LLC NY Methode Mfg Co Rolling Meadows Ill Bendix Corp Franklin Ind Weckesser Co Inc Chicago lii Amphenol Corp Janesville Wis Industrial Retaining Ring Co Irvington N J IMC Magnetics Corp Westbury N Y Sealectro Corp Mamaroneck N Y ETC Inc Cleveland Ohio International Electronic Research Corp Burbank Calif Renbrandt Inc Boston Mess RW cz C3 4 C5 7 C8 cg C10 C11 14 C15 Ci6 C17 18 CR1 4 CR5 8 CRS CR10 11 CR12 15 CR16 17 CR18 CR19 CR20 J1 2 J3 4 R18 R19 R20 R21 R22 R23 R24 R25 Table 6 4 R ide Parts HP PTI interconnect and Power Supply Board Not Assigned fxd elect 100uF 25Vdc fxd elect 325uF 35Vdc j fxd cer OSuF 400Vdc fxd elect 200uF 175Vdc fxd cer O5uF 400Vdc fxd elect 6000uF 50Vdc fxd cer 0 5uF 400Vdc fxd elect GOOQuF S0Vdc fxd elect 200uF 175Vdc fxd cer 47uF 25Vdc Diode Si 200mA 75V Diode Si 200prv 1A Not Assigned Diode Si 400V 1A Diode Si 200V 1 5A Dio
71. control until front panel am 5 9 BPS A UNDER TEST RESISTOR CURRENT SAMPLING RESISTOR DIGITAL OR DIFFERENTIAL VOLTMETER DVM Figure 5 10 Constant Current Test Setup meter indicates maximum rated negative output current f DVM should read 2 0V 5 46 Source Effect Line Regulation Definition The change AtouT in the static value of dc output current resulting from a change in ac input voltage over the specified range from low line lusually 104 volts to high line usually 127 volts or from high line to low line To check the line regulation proceed as follows a Utilize test setup and front panel settings of Paragraph 5 45 b Connect variable auto transformer between in put power source and power supply power input c Adjust auto transformer for 104Vac input d Turn VOLTAGE control fully clockwise e Adjust CURRENT control until front panel am meter reads exactly maximum rated positive output current f Read and record voltage indicated on differential voltmeter g Adjust variable auto transformer for 127Vac input h Reading on differential voltmeter shouid not vary from reading recorded in step f by more than 450uV i Turn VOLTAGE control fully counterclock wise and repeat steps e through h for negative output current 5 17 Load Effect Load Regulation Definition The change Alout in the static value of the dc output current result ing from a change in load resistance
72. could resuit in personal injury If the instrument is to be energized via an external autotransformer for voltage reduction be certain that the autotransformer common terminal is connected to the neutral earthed pole of the ac power lines supply mains INPUT POWER MUST BE SWITCH CONNECTED For instruments without a built in line switch the input power lines must contain a switch or another adequate means for disconnecting the instrument from the ac power lines supply mains DO NOT OPERATE IN AN EXPLOSIVE ATMOSPHERE Do not operate the instrument in the presence of flammabie gases or fumes KEEP AWAY FROM LIVE CIRCUITS Operating personnel must not remove instrument covars Component replacement and internal adjustments must be made by qualified service personnel Do not replace com ponents with power cable connected Under certain condi tions dangerous voltages may exist even with the power cable removed To avoid injuries always disconnect power discharge circuits and remove external voltage sources before touching components DO NOT SERVICE OR ADJUST ALONE Do not attempt internal service or adjustment unless another person capable of rendering first aid and resuscitation is present DO NOT EXCEED INPUT RATINGS This instrument may be equipped with a line filter to reduce electromagnetic interference and must be connected to a pro perly grounded receptacle to minimize electric shock hazard Operation at line
73. ct electrolytic encap encapsulated F farad OF degree Farenheit fxd fixed Ge germanium H Henry Hz Hertz IC integrated circuit ID inside diameter inend incandescent k kilo 103 m milli 10 M mega s 109 micro 10 met metal mtr manufacturer mod modutar or modified mtg mounting n nano 10 NC normaliy closed NO normally open NP nickel plated LI ohm obd order by description outside diameter pico 1012 printed circuit potentiometer peak to peak parts per million 7 peak reverse voltage rectifier rms e root mean square Si silicon SPDT single pole double throw SPST single pole single throw SS smail signal T 7 slow blow tantulum Ti titanium Vi volt var variable ww wirewound W Watt Table 6 3 Code List of Manufacturers CODE MANUFACTURER ADDRESS EBY Sales Co Inc Jamaica N Y Aerovox Corp A New Bedford Mass Sangamo Electric Co S Carolina Div Pickens S C Alien Bradley Co Milwaukee Wis Litton Ind l Beverly Hills Calif TRW Semiconductors Inc Lawndale Calit Texas Instruments inc Dallas Texas RCL Electronics Inc Manchester N H Amerock Corp Rockford HL Sparta Mfg Co Dover Ohio Ferroxcube Corp Saugerties N Y Fenwal Laboratories Morton Grove Ill Amphenol Corp Broadview IH Radio Corp of America Solid State and Receiving Tube Div Somerville N J
74. current limiting circuits monitor the output voltage and current The voltage limiting circuit prevents the output voltage from exceeding approxi mately 10 of the maximum rated output voltage The current limiting circuit limits the output current to a value approximately two times the nominal rated output in order to protect the instrument during the transition from con stant voltage to constant current operacion 4 12 The turn on off circuit protects the load from power turn on and turn off transients by shorting the BPS A output and disabling the amplifier and driver circuits during turn on and turn off 4 13 The bias supply converts the ac input to regulated dc voltages which are used throughout the instrument for _biasing purposes Also the reference voltages used in the voltage and current comparison circuits are derived from the bias voltage In addition the bias supply provides the voit age to operate the turn on off circuit 4 14 Meter circuits are provided for monitoring the BPS A output voltage and current ac and dc Compensa tion circuits are included for meter loading effects 4 15 CONSTANT VOLTAGE CONSTANT CURRENT OPERATION 4 16 in order to maintain a constant voltage output the voltage comparison amplifier tends to achieve zero output impedance by altering the output current whenever the load resistance changes in order to maintain a constant output current the current comparison amplifiers attempt to achieve i
75. d enter any listed changes s in the manual cpl ihe Vlr A UM Sp e Z HI yna SE a LN wg E RE AE UU TR UN mir H SERIAL MAKE ea A MaMa CHANGES Prefix Number i i pM All i Errata 13244 00106 00125 i 1 1517A 1 00126 00180 1 2 16064 00141 00150 1 3 16128 i 00151 00320 1 4 i i 18084 1 00321 00335 1 1 5 3 1818A i 00336 00735 1 6 i 20484A 00736 00815 1 7 i 1 21254 00816 00865 1 8 i 2142A i 00866 00920 1 9 1 22294 00921 01000 1 10 i 23124 01001 01110 1 11 14 24164 1 01111 01150 1 12 14 24374 01151 01480 1 14 i 28334 01481 01490 1 15 i 2844A 1 01491 01690 1 16 i ES 31158 01691 up 1 1 17 t 1 i i i t t i H i i ERRATA In paragraph 2 19 change the last sentence to read Make sure that the correct fuse is installed if the position of the slide switch is changed IA for 115 V operation and 5 A for 230 V operation In paragraph 3 4 change the third sentence to read The power module contains fuse F1 IA for 115 Vae or 5 A for 230 Vae and a slide switch for connecting 115Vae or 230Vac input power to the instrument In Figure 3 14 the V I quandrant should read SINK Change paragraph 7 4 to read This diagram Figure 7 1 shows the relationship between the instrument as semblies and ties the schematic diagram sheets together ij the following to the Option No 007 ten Pn Option Voltage Control description in
76. d negative output lines respectively The series regulators are controlled by the positive and neg ative driver circuits on board A3 When the positive driver circuits are in control the series regulators Q1 and Q2 are conducting and the series regulators Q3 and Q4 are turned off For this condition the supply furnishes a positive out put The reverse is true when the negative driver circuits are in control Q3 and O4 are turned on Q1 and Q2 are turned off and the supply provides a negative output 4 27 Note that NPN power transistors Q1 and Q2 and associated NPN driver transistors A3012 and A3Q14 through A3Q16 are connected as cascaded emitter followers which respond to a positive going signal In order to respond to negative going signals NPN power transistors Q2 and Q3 are connected with PNP driver transistors A3013 and A3Q17 through A3Q19 in a pseudo PNP configuration using local feedback This configuration allows NPN power transistors to be employed as series control elements for negative out puts 4 28 During amplifier operation the transistors serve as a single ended push pull output amplifier Although the schematic shows Q1 Q2 and Q3 04 drawn as a convention al series regulator the circuit could be redrawn as a push pull amplifier without changing any of the connections The output amplifiers are biased for class AB operation and are connected in a complementary configuration 4 29 Coupling Amplifier and Driver C
77. d to the right and component location diagram is unfo ded to the left 7 7 SCHEMATIC DIAGRAMS 7 8 The schematic diagram Figure 7 2 consists of two sheets Sheet 1 illustrates the Output Power Amplifier Cir cuits and Sheet 2 illustrates the Voltage and Current Control Circuits 7 8 Test points encircled numbers appear on the schem atics These points coincide with the test points on the component location diagrams and are referred to in the text
78. dance 100M8S2 min gain Option 001 Digital Accuracy 0 00476 Measure dc voltages calibration HP3462A or Voltmeter Sensitivity 14V floating input procedures HP3420B Oscilloscope Sensitivity and bandwidth 1mV Measure ripple display transient HP180A plus cm and SOMHz recovery waveforms measure noise 1801A and 1821A spikes Measure response plug ins Function 100H2 squarewave and sinewave Measure frequency response and HP3310A Generator output impedance Distortion Accuracy 3 from 10Hz to Measure amplifier distortion HP331A Analyzer 1MHz Variabie Voltage Current rating 2A Range 90 Vary ac input for high line to low Transformer 130Vac Equipped with voltmeter line regulation accurate within 1 volt Repetitive Load Rate 60 400Hz 2usec rise and Measure transient response See Figure 5 4 Switch fall time Current Sampling Value 182 t 196 24W Measure output current calibrate Resistor i ammeter Resistive Loads Value See Figure 5 1 1 50W Terminating Value 50 ohms ZW 596 non Noise spike measurement Resistors inductive 4 required Blocking Values O0iuF 100Vdc 2 Noise spike measurement output Capacitors required 1000uF 60Vdc 1 impedance measurement required Programming Resistors 0811 2958 0811 2959 Micro Ohm Type 132F 10 24K 05 20 48K 05 5 1 5 5 PERFORMANCE TEST 5 6 The following test ca
79. de Si 400V 1A Diode Hot Carrier Not Used Jumper Diode Hot Carrier Connector Printed Circuit Edge Connector Multi contact Relay 6Vdc coil voltage Power PNP Si SS NPN Si Power NPN Si SS PNP Si var ww 100 5 1W fxd comp 22K 5 AW fxd comp 2K 5 1W fxd comp 22K 5 ZW var ww SK 5 1W fxd film 3K 195 1 8W fxd film 34 8K 1 1 8W Not Used Jumper var ww 5K 5 1W fxd film 3K 196 1 8W Not Used Jumper fxd film 11 3K 1 1 8W fxd film 1 69K 1 1 8W var ww 200 5 1W fxd film 1 69K 1 1 8W var ww 200 5 1W fxd film 2 37K 1 1 8W fxd film 100K 1 1 8W fxd film 471 1 1 8W fxd film 6 2K 1 1 8W fxd comp 4 3K 5 W 6 5 1 2 21 1 1 1 1 1 3 2 2 30D107G025DD2 DSM D34656 DEE 33C17A3 CDH 68D10223 33C17A3 CDH 36D7890 33C17A3 CDH 36D7890 68D10223 5C11B7 CML 1N4148 1N5095 1N5060 1N4999 1N5060 252 18 30 340 3428 2002 603 6 2N4036 2N4141 2N1711A 2N2907 CT 106 4 EB 2235 G82025 82235 CT 100 4 CEA T 0 CEA T 0 CT 100 4 CEA T 0 CEA TA CEA TO CT 100 4 CEA T 0 CT 100 4 CEA T 0 CEA T 0 CEA T 0 CEA T 0 EB 4325 0180 0094 0180 0332 0150 0052 0180 1885 0150 0052 0180 0449 0150 0052 0180 0449 0180 1885 0160 0174 1901 0050 1901 0327 1901 0328 1901 0416 1901 0328 1901 0535 1901 0518 1251 2134 1251 3119 0490 0745 1853 0041 1854 0071 1854 0244 1853 0099 2100 1755 0686 2235 0689 2025 0686 2235
80. e before and after the imposed load change and Z is the specified load current change of the full load current rating of the supply 5 20 Transient recovery time may be measured at any input line voltage combined with any output voltage and load current within rating 5 30 Reasonable care must be taken in switching the load resistance on and off A hand operated switch in series with the load is not adequate since the resulting one shot displays are difficult to observe on most oscilloscopes and the arc energy occurring during switching action completely masks the display with a noise burst 5 31 A mercury wetted relay as connected in the load switching circuit of Figure 5 4 should be used for loading and unloading the supply When this load switch is connec ted to a 60Hz ac input the mercury wetted relay will open and close 60 times per second Adjustment of the 25K con trol permits adjustment of the duty cycle of the load current switching and reduction in jitter of the oscilloscope display POWER SUPPLY UNDER TEST OSCILLOSCOPE CONTACT PROTECTION NETWORK 052 5w O 4F NOTE 3 NOTES i THIS DRAWING SHOWS A j SUGGESTED METHOD OF BUILDING A LOAD SWITCH HOWEVER OTHER METHODS LANE COULD BE USED SUCH AS SWITCH A TRANSISTOR SWITCHING NETWORK MAXIMUM LOAD RATINGS OF LOAD SWITCH ARE SAMPS SOOV 250W INOT 2500W 2 USE MERCURY RELAY CLARE TYPE HGP 1002 OR WE TYPE 2768 itsyac j 3 USE WIRE WOUND
81. e junction of A2K2 K3 and CR4 anode is removed from 2 return which disables the relays to their normally open condition However with A5S2C in the X1 position the return to is completed and the relays are activated from the 15Vdc bias supply With RANGE switch A5S2C in the REMOTE position remote selection of the X1 or X4 range is allowed via rear terminal A11 4 48 Changes in the error signal magnitude and polarity instantaneously cause the summing point potential to change This change causes comparison amplifier A2U1 to provide the proper correction voltage to the low level amplifier and driver circuits The correction voltage levels at the low level amplifier input are from approximately 2 5V to 4 5V and correspond to the output voltage range of 30V to 20V A correction voltage of approximately 3 5V corres ponds to an output voltage of OV Zener diode A2VRB diodes A2CR20 and CR21 and resistor A2R41 prevent A2U1 from going deep into saturation Diodes A2CR18 and A2CR19 limit the maximum input to the comparison amplifier thus protecting it from overvoitage conditions Variable resistors A2R60 and A2R61 connected to the 6 2V and 6 2V reference voltage circuits through resis tors A2R36 to A2R39 and A2R51 through A2R54 are used for output zero and offset adjustments Relay A2K1 opens the input path to A2U1 when the BPS A is remotely controlied and the programmed data is changed thus pre venting data transient
82. e or negative depending on other control settings 5 72 The A2 plug in board contains the voltage and cur rent control circuits which can be separated functionally allowing the troubie to be isolated to the individual circuit level The following paragraphs provide troubleshooting procedures for the voltage control current control and RMS current meter driver circuits located on board A2 5 73 Voltage Control Circuits Integrated circuit ampli fies A2U1 voltage comparison amplifier and A2U2 voit age reference gain control amplifier with their circuit com ponents are part of the constant voltage feedback loop The following procedure consists of a series of fast checks to iso late trouble in these circuits a Remove top and right side covers from instru ment Remove the A3 board b Ensure that rear terminal strip is strapped cor rectly for local operation see Section iti c Set front pane controls as follows MODE switch POWER SUPPLY RANGE switch X1 VOLTAGE control fully counterciockwise CURRENT control fully clockwise d Connect a DVM between A2U2 pin 6 TP14 and S e Turn VOLTAGE control through its range and observe that DVM reading varies from 0 to 10V If vott age reading is correct proceed to step f If the output at pin 6 is 15V check A2CR1 CR2 U2 for short circuits 1f the output at pin 6 is zero VOLTAGE control A5R2 is open or defective or A2U2 is defective f Set VOLTAGE co
83. e variable gain is from O to 8 in the high range and from O to 2 in the low range CAUTION The voltage applied to the input terminals M IN A1 and LO IN A2 must not exceed 50V maximum or the instrument may be damaged 3 47 Resistance Programming Constant Current Pro gramming resistors RpC connected as shown in Figure 3 6 can be used to control the constant current output The front panel CURRENT control is disconnected disabled when the remote Rpg resistors are connected as indicated Resistance programming of the constant current output can be accomplished in all three modes of operation power supply variable gain amplifier and fixed gain amplifier 3 7 individual precision 0 05 Rpc resistors contro positive and negative constant current outputs respectively The pos itive or negative output current is variable from O to 2 048A at a rate determined by the programming coefficient as foi lows 5 ohms mA 1 CAUTION A load must be maintained at all times during constant current operation The load can be a 40KX1 resistor 3 48 Zero output current for zero programming resis tance can be assured through proper adjustment of the front panel i and ZERO ADJ potentiometers see Paragraph 5 107 3 49 Voltage Programming Constant Voltage Voltage programming of the output voltage can be accomplished in the variable gain or fixed gain amplifier mode of operation Voltage progra
84. ed in the BPS A described by this manual When replacing a semiconductor use a Hewlett Packard part or a commercial replacement part if applicable in cases where neither of these parts are immediatiey available and a part is needed for emergency operation or troubie shooting verification the alternate part see Table 5 5 can be tried with at least a 9096 probability of success 5 86 COVERS AND FRONT PANEL 5 87 Top or Bottom Cover To remove either the top or bottom cover a Turn off unit b Remove two inch No 6 setf tapping flat head screws at rear of cover c Slide cover toward rear of unit approximately 3 4 inches and lift out of unit 5 88 Side Cover To remove either side cover remove four 1 4 inch No 6 flat head screws and lift cover off 5 21 5 89 Side Castings To remove either side casting a Remove top bottom and side cover b Remove eight No 6 flat head screws securing side casting to instrument cross members c Lift side casting off 5 90 Front Panel To remove the front panel a Remove top bottom side covers and left side casting b Loosen the VOLTAGE METER and CURRENT METER knobs with allen wrench and remove knobs c Front panel may now be pulled forward away from front of unit 5 91 Foot Assemblies and Tilt Stand The front and rear foot assemblies and the tilt stand on the bottom of the unit must be removed before the unit is rack mounted see Paragraph 2 15 To remove the
85. er supply must be allowed to thermally stabilize for a sufficient period of time at each measurement temperature 5 37 The temperature coefficient given in the specifica tions is the maximum temperature dependent output voltage change which will result over any one degree Centigrade in terval The differential voltmeter or digital voltmeter used to measure the output voltage change of the supply should be placed outside the oven and should have a long term stability adequate to insure that its drift will not affect the overall measurement accuracy 5 38 follows a Connect load resistance high range and differ ential voltmeter as illustrated in Figure 5 1 To check the temperature coefficient proceed as NOTE Connect voltmeter to S terminals NOT across load b Set MODE switch to POWER SUPPLY and RANGE switch to X4 Turn CURRENT control fully clockwise Adjust front pane VOLTAGE control until front panel voltmeter indicates maximum rated output voltage d Place power supply in temperature controlied oven differential voltmeter and load remains outside oven Set temperature to 30 C and aliow 30 minutes for stabilization e Record differential voltmeter reading f Raise temperature to 40 C and allow 30 min utes for stabilization g Observe differential voltmeter reading Differ ence in voltage reading between step e and g should be less than 35mV h Repeat steps a through g with low range X
86. eration and becomes a constant current source still fur ther decreases in the value of load resistance are accompan ied by a drop in the supply output voltage with no accom panying change in the output current value With a short circuit across the output load terminals lout is and EOUT 0 CONSTANT VOLTAGE CONSTANT CURRENT OBERAT ING REGION y CONSTANT VOLTAGE LOA RATION REGION Eg tFRONT PANEL VOLTAGE CONTROL SETTING OF REMOTE PROGRAMEING SETTING Lex FRONT PANEL CURRENT CONTROL SETTING OR REMOTE PROGRAMMING SETTING E ber Fee CRITICAL OR CROSSOVER VALUE OF 3 LOAD RESISTOR Figure 4 2 CV CC Operating Locus 4 17 Thus at voltage and current settings within the bi polar ranges the crossover value of load resistance can be defined as Rc Eg ig Adjustment of the voltage and cur rent settings permits this crossover resistance Re to be set to any desired value within the rating of the instrument if the magnitude of Ry is greater than RC the supply is in constant voltage operation 4 18 DETAILED CIRCUIT DESCRIPTIONS 4 19 GENERAL 4 20 The following paragraphs provide detailed circuit descriptions of BPS A Model 6825A The descriptions are based on simplified schematic of Figure 7 1 and the detailed schematic of Figure 7 2 Sheets 1 and 2 The simplified schematic illustrates in simplified form the circuitry depic ted on Sheets 1 and 2 of Figure 7 2 The
87. eration until they can be repaired by qualified service personnel TABLE OF CONTENTS PAGE PAGE GENERAL INFORMATION sess nnne TT PRINCIPLES OF OPERATION EA UT PL 1 1 Description isis eee entente pany Eesen 1 1 4 1 Overall Description esee 4 1 1 3 Power Supply Features eessen 1 1 4 2 General EE d 1 7 Amplifier Features Een 1 1 44 Block Diagram Description seseeseeeree 4 2 1 10 a EEN 1 1 4 15 Constant Voltage Constant Current Operation 4 3 1 12 Specifications sc fue in edis 1 1 4 18 Detailed Circuit Descriptions OE n 4 4 1d4 Se sie Eo ennt 15 QD ANC EE ees d 1 16 Accessories EEN en RZE 1 5 4 24 Output Power Amplifier Circuits 7 1 18 instrument identification essere eren 1 5 Figure 7 2 Sheet 1 DE 1 21 Ordering Additional Manuals ess 15 4 40 Voltage and Current Control Circuits INSTALLATION osoaren EN Figure 7 2 Sheet 2 4 6 2 1 Initial Inspection cucine eorom one Daran open naa 2 1 2 3 Mechanical Check se zai EE 2 1 MAINTENANCE ee RUE oe 5 1 2 5 Electrical Check 111 Stee shiva Ee 5 1 Introduction Leod nilo cO Seed 5 1 2 7 Repackaging for Shipment KEREN 2 1 5 3 Test Equipment Required ENEE 5 1 2 9 Installation Data WO TOO DA ES e 21 5 5 Performance Test SE SOME D2 2 ET o cT 2 1 5 7 Power Supply Mode Tests EE
88. eries regulator output amplifier The 45 volt outputs are the bias supply voltages for the amplifier and driver circuits on board A3 4 24 Bias Supply The bias supply circuit provides stable 15 volt outputs which are used throughout the instrument for biasing purposes and to develop the reference voltages The bias supply also provides 20 volt filtered and unfiltered auxiliary outputs Two series regulator type circuits main tain the 15 volt outputs constant Since the circuits are identical only the 15 volt circuit is discussed Transistor A102 is a voltage comparison circuit that compares the 15 volt output with a fixed reference voltage The 15 volt 4 4 output is applied to the base circuit of A102 through resis tors ATR29 and A1R30 whereas the reference voltage is _ furnished in the emitter circuit by ATVR1 If the 15 volt output changes voltage comparator A1Q2 produces an error signal which is applied to the base of series regulator A1Q1 The error signal causes A1Q1 to change its conduction so as to correct the output voltage 4 25 Series Regulator Output Amplifier NPN power transistors Q1 through O4 mounted on the heat sink assem bly are utilized as series regulators during power supply op eration and as a single ended push pull amplifier during am plifier operation 4 26 During power supply operation parallel connected transistors Q1 Q2 and Q3 O4 serve as series control ele ments in the positive an
89. fully counterclockwise and turn on the BPS A i Adjust A2R21 for 2 048V 5mV as indicated on DVM m Turn BPS A off and remove the jumper between A18 and A13 Connect a precision 10 24K 0 5 resistor between A18 and A13 n Turn VOLTAGE control fully ciockwise and turn on the BPS A 5 24 o Adjust A2R19 for 2 048V 5mV as indicated on DVM 5 108 DC Ammeter Calibration a Set the CURRENT METER switch to the 2 4A DC position b Adjust A1R20 for a front panel ammeter indica tion of 2 0A c Turn off BPS A Remove the 10 24KQ resistors replace jumpers from A20 to A21 and from A13 to A14 Ensure that jumpers are also connected from A12 to A13 and from A19 to A21 Replace top cover 5 109 AC METER CALIBRATION 5 110 AC Voltmeter Calibration a Remove top cover to gain access to potentio meters on board A1 b Connect test setup as shown in Figure 5 16 with high range load resistor R connected in series with 10 resistor Rc across and output terminals Set function generator for a 5 volt 100Hz squarewave output c Set BPS A front panel controls as follows MODE switch FXD GAIN AMP RANGE switch X4 VOLTAGE control May be left in any posi tion for this procedure CURRENT control fully clockwise VOLTAGE METER 16V AC CURRENT METER 1 6A AC d Turn on BPS A and atlow a 10 minute warmup e Connect oscilloscope to S and S terminals and observe waveform for overshoot and ringing f Remove oscilloscope
90. ge A2U2 defective see Paragraph 5 71 VOLTAGE control A5R2 defective MODE switch not in proper position Zero or low output voltage POWER SUPPLY mode only Zero or low output voltage POWER SUPPLY and VAR GAIN AMP modes only No output VAR GAIN AMP and FXD GAIN AMP modes only b improper connections to rear terminals A1 and A2 or front panel terminals HI IN and LO IN a RANGE switch defective b Relays A2K2 and or A2K3 defective Output voltage correct in X4 range but incorrect in X1 range or vice versa Negative output normal but zero or low positive output Check the main positive supply voltages see Tabie 5 2 35V 45V b Positive turn on off circuit defective A202 shorted c Defective positive output power transistor stage on heat sink assembly Q1 or Q2 defective d Defective positive coupling amplifier or driver stages on A3 board A3Q6 Q7 Q8 opened VR2 shorted Output voltage latched to maxi mum positive Amplifier stage on A3 board defective A3Q6 shorted b Positive current comparison amplifier output diode A2CR 14 shorted 5 16 Tabie 5 3 Overall Trouble isolation Guide Continued SYMPTOM PROBABLE CAUSE Positive output normal but zero Check the main negative supply voltages see Table 5 2 35V 45V or low negative output b Negative turn on off ci
91. ge feedback path aliows high or low range scaling of the output in all three modes of operation The range control circuit may be controlled locally front panel RANGE control or remotely rear terminal strip The range control circuit is described in detail in Paragraph 4 47 4 10 The current comparison amplifiers control the switching of BPS A operation between constant voltage and constant current see Paragraph 4 15 and provide a constant current output when the BPS A is operating as a constant cutrent source During constant current operation positive and negative current comparison amplifiers detect any difference between the voltage drop across the current sampling resistor and a fixed stable reference The voltage across the sampling resistor is applied to the amplifiers through the front panel CURRENT contro or remote cur rent programming Control Any change in load current whether by variation of the CURRENT contro resistance or remote current programming input or by changes in the current through the current sampling resistor causes an error voltage proportional to the current to be applied to the amplifier and driver circuit Consequently the series regulator output amplifier conduc tion will be altered thereby restoring the load current to some initial value Either the positive or the negative current comparison amplifier can be in contro depending upon the polarity of the current 4 11 The bipolar overvoltage and
92. ge the Tor cover to HP P N 5000 9367 qty 1 i ERRATA In the replaeable parts list Page 6 10 delete Terminal Block TQ 3 HP Lt 0360 1766 and in its place added Termi Block TQ 3 HP P N 0360 2161 CHANGE 9 In the manual page 4 5 paragraph 4 36 change reference designator R37 to R72 In paragraph 4 37 change the first sentence to read At turn off the 20 V unfiltered supply voltage is removed and relay A1K1 is deenergized In the replaceable parts table under At Interconnect and Power Supply Board make the following changes Delete R32 fixed 1 3k 25 W HP P N 0757 0735 Add R72 fixed 18 k 5 W HP P N 0686 1835 R73 fixed 5 1 k 5 W HP P N 0686 5125 CR21 Diode Si 200 prv HP P N 1901 0327 VRh Diode zener 11 8 V HP P N 1902 3180 Change C2 to 3 3 uF 15 V HP P N 0180 2264 CRh to SCR HP P N 1884 0074 R37 to 390 ohm 3 W HP P N 0811 1799 In Figure 7 2 Sheet 1 change the schematic as follows E RY Tea menen t 390 ahm JW KI R72 CR yt c2 AA CRA R73 5 4K VEN In the replaceable parts table page 6 5 and on the schematic Figure 7 2 Sheet 1 change R21 to 2 61 k 1 8 W HP P N 0698 0092 the value of R21 must be selected for optimum performance This change supersedes the Errata change made on page 2 CHANGE 10 In the replaceable parts list on page 6 5 change R1 2 3 to var ww 100 10 HP P N 2100 3349 On page 6 11 under Fro Panel Mechanical change output Panel to lu P N 5000 318
93. h a serial prefix of 2315A or above To adjust units with serials prefixed 23154 or above or any unit with a 10 turn poten tiometer for the voltage control follow steps i and j unless the power supply is ex pected to be used in a remote programming application i Reconnect jumper A8 A9 and remove remote programming connections j Cheek the output voltage with the VOLTAGE control fully clockeise The DYM should read greater than 20V If not readjust A2R58 for a DVM reading of 20 5V This will assure control of the output volt age over the full specified range when using the front panel control ERRATA In the Operating and Service manual change Section 2 19 to read as follows The power supply may be operated from either a nominal 115 volt or 230 volt 48 63 Hz power source When the instrument leaves the fac tory the proper internal external voltage selection line cord plug and fuse have been installed to operate with the mains voltage frequency and outlet receptacle of the country of destination Make sure that the correct fuse is installed if the mains voltage is changed CHANGE 15 In the parts list and on the schematic change for the A2 board change R3 from 714 ohms 1 1 4W to HP P N 0811 1935 to 400 ohms HP P N 0811 1930 qty of 1 CHANGE 16 In the replaceable parts list and on the schematic change VR1 VR4 from 6 2V 5 HP P N 1902 0777 to 6 2V 2 HP P N 1902 0509 qty 4
94. he various operational capabilities of the power supply A more theoretical description concerning the operational features of this supply is contained in Application Note 90 and in various Tech Letters Copies of these can be obtained from your local Hewlett Packard field office 324 LOCAL PROGRAMMING 325 The BPS A is shipped with its rear terminal strap ping connections arranged for constant voltage constant current local programming local sensing single unit mode of operation This strapping pattern is illustrated in Fig re 3 4 Also the Local Auto switch on board A2 see Para graph 3 54 is in the Local position when the instrument is shipped from the factory This switch must be in the Local position for single unit mode of operation 326 The operator selects either power supply variable gain amplifier or fixed gain amplifier operation MODE switch and also selects either constant voltage or a constant current output using the front panel VOLTAGE and CUR RENT controls for local programming no strapping changes are required Constant voltage or constant current opera tion are selected as described in the following paragraphs wi A8 A9 AIO Ail AI2 AIS And eleielela eie w wau AS AIG AI AIB AI9 A20 A2 ejeiejeelaoe w U Figure 3 4 Normal Strapping Pattern LOCAL Programming 3 27 Constant Voltage To select a constant voltage output proceed as follows a Remove load from output termi
95. ility of the scope be verified by shorting together its two input feads at the power supply and observing the trace on the CRT If this trace is not a straight line then the scope is not rejecting the ground signa and must be realigned in accordance with the manu facturer s instructions until proper common mode rejection is attained 5 25 follows To check the ripple and noise output proceed as a Connect the oscilloscope or RMS voltmeter as shown in Figures 5 2B or 5 2C Set MODE switch to POWER SUPPLY Turn CURRENT control fully clockwise b Adjust VOLTAGE control in the X1 and X4 ranges until front panel meter indicates maximum rated out put voitage Check both maximum rated positive and nega tive output voltages The observed ripple and noise should be less than X1 Range X4 Range 1 5mVrms 4mVp p 5mVrms 15mVp p 5 5 5 26 Noise Spike Measurement When a high frequency spike measurement is being made an instrument of suffic ient bandwidth must be used an osciltoscope with a band width of 20MHz or more is adequate Measuring noise with an instrument that has insufficient bandwidth may conceal high frequency spikes detrimental to the load 5 27 The test setups illustrated in Figures 5 2A and 5 28 are generally not acceptable for measuring spikes a differential oscilloscope is necessary Furthermore the measurement concept of Figure 5 2C must be modified if accurate spike measurement is to be achieved a As
96. in instrument g Turn on power If output voltage is normal max positive the turn on off circuit A301 A3Q5 is defective If output is zero or low proceed to step th h Turn off power and reconnect diodes A3CR3 and A3CR4 Connect 5Vdc to the A1 HI IN and A2 LO IN terminals i Set MODE switch to FXD GAIN AMP position and turn on power If output voltage is normal max posi tive the voltage gain reference stage A2U2 is probably de fective see Paragraph 5 71 If output is zero proceed to step ij j Turn power off Remove the A2 board Con nect a variable dc voltage source 2 5V to 4 5V between A3 pin 5 and 2 Connect negative potential to A3 pin 5 k Turn on power and vary the negative source voltage from 2 5V to 4 5V Output voltage should vary accordingly from maximum positive to maximum negative value through zero If output voltage is normal the A2 board is defective see Paragraph 5 71 If output is not normal the A3 board or output power transistor stages on heat sink assembly are defective see Paragraph 5 76 5 71 A2 BOARD TROUBLESHOOTING NOTE For normal operation of the BPS A the Local Auto switch A2S1 must be in the Local posi tion see Figure 3 9 The Auto position is used only for auto series auto parallel or auto tracking operation see Section HI If this switch is left in the Auto position for normal operation the output will be latched at full positiv
97. inimum current is attained as indi cated on meter i Turn off supply and remove short from output term inals L Turn on supply and adjust VOLTAGE CONTROL for an output of 20V k Turn off supply and reconnect short across the HI and LO OUT terminais L Turn on supply and note that CURRENT MODE in dicator lights and meter indicates O volts m Adjust CURRENT control from full ew to full cow and note that minimum current is attained as indi cated on meter n Turn off BPS A and remove short from output term inals VARIABLE GAIN AMPLIFIER CHECKOUT PROCEDURE o Set front panel controls as follows MODE switch 3 VAR GAIN AMP RANGE switch 4 X1 VOLTAGE control midposition CURRENT control 5 full clockwise VOLTAGE METER switch 8 low range AC CURRENT METER switch QQ high range AC p Connect a 1 75V rms 100Hz input signal to the front pane input terminals H1 and LO IN q Turn on supply and adjust VOLTAGE control through entire RMS range and note that maximum voltage is attained as indicated on meter r Set VOLTAGE METER switch to high range AC RANGE switch 4 to X4 and adjust VOLTAGE control through entire RMS range and note that max imum voltage is attained as indicated on meter FIXED GAIN AMPLIFIER CHECKOUT PROCEDURES s Set MODE switch 3 to FXD GAIN AMP posi tion and increase input signal to 3 5V rms t Adjust VOLTAGE control through entire RMS range
98. ions Three Units 3 64 REVERSE VOLTAGE AND CURRENT LOADING 3 65 Current limit circuits also protect the BPS A from active loads that force energy in or out of the BPS A sink condition This can appear as current flow into the HI OUT terminal when the terminal is positive or current flow out of the terminal when it is negative Figure 3 14 shows the normal operating iocus of the BPS A As shown the 6825A BPS A will limit the sink current to a value ranging linearly from 2A at OV to 1A at 20V 3 66 An active load can easily be accommodated by the BPS A as tong as the following precautions are adhered to a The active load must not be applied unless the BPS A is in its active state b Program to zero output before disconnecting load CAUTION Externally applied voltage to output terminals n excess of 25V could damage the instrument Figure 3 14 6825A Output Ranges 3 12 SECTION IV PRINCIPLES OF OPERATION RECTIFIERS SERIES Am CLE ED we ous CONTROL CIRCUITS i REF GAIN d RE CONTROL MODE p i AMPLIFIER AMPLIFIER CIRCUIT SELECTION AMPLIFIER ANG DRIVER SWITCH M CIRCUITS MR EXTERNAL BIPOLAR AC OR C CURRENT wu SINK eRT F i POSITIVE i POSITIVE CURRENT CURRENT REF COMPARISON IPLIF mar ara REF REF ERENCE s WHT SUPPLIES REGATIVE 3 t CURRENT COMPARISON NEGATIVE AMPLIFIER CURRENT REG Das t REF WOLI 9 Our CURRENT SAMPLING BIAS RESISTOR Bik SUPPLIES y
99. ipolar DC voltage from a maximum negative value through OV to a maximum positive value DC accuracy is 5396 of full scale The lower scale reads the RMS output voltage from 0 to a maximum level AC accuracy is 596 of full scale The voit meter ranges selected by the VOLTAGE METER switch are as follows Dc AC RMS 0 to 2 4V 0 to 1 6V uncal Oto 24V O to 16V 3 18 CURRENT METERING 319 The CURRENT METER switch permits monitoring the DC or AC output current on ammeter The shaded area on the ammeter face indicates the amount of output current that is available in excess of the normal rated output The ammeter upper scale reads the bipolar DC current from a maximum negative value through OA to a maximum positive value DC accuracy is 3 of full scale The lower scale reads the RMS output current from 0 to a maximum level AC accuracy is 5 of ful scale The am meter ranges selected by the CURRENT METER switch are as follows DC AC RMS 0 to 0 24A 0 to 0 16A 0 to 2 4A 0 to 1 6A 3 20 TURN ON CHECKOUT PROCEDURES CAUTION Rear terminal strip cover must be in place when instrument is in use 3 21 The following turn on and checkout procedures are performed utilizing the front panel controls Figure 3 2 and the norma rear terminal strapping connections as re ceived from the factory Also the Local Auto switch lo cated inside the instrument on board A2 is in the Local position pushed to the right o
100. ircuits The coupling amplifier and driver circuits on board A3 amplify the error signal received from the voltage and current control circuits on board A2 This amplified signal controls the conduction of the series regulator output amplifier transistors thus control ling the amplitude and polarity of the BPS A output The am plifier and driver circuits consist of positive amplifier and driver stages 06 08 Q12 014 016 and negative amplifier and driver stages Q9 O11 Q13 Q17 Q19 on board A3 4 30 X The error signal from the voltage or current control circuits is applied to the positive and negative voltage control amplifier circuits on board A3 For a positive going control signal the positive amplifier conducts more and the negative amplifier less The reverse is true for a negative going control signal Since the positive and negative sections of the ampli fier and driver are symmetrical only the positive section is discussed in detail 4 31 The positive voltage coupling amplifier is comprised of transistor stages Q6 Q7 and Q8 Coupling amplifier stage Q7 serves as a level changihg transistor coupling the error signal to the output driver circuits The gain of the coupling amplifier is about 1 6X Notice that the supply voltages for the input circuits are low level and referenced to 2 com mon see Figure 7 2 sheet 2 The other amplifier and driver stages however use high level supply voltages 35 and 45V that
101. is similar in principle for the positive voltage case Front panel controls 1 ZERO A1R2 and ZERO A1 R3 in the positive and negative current reference circuits are used to adjust the respective zero for programming accuracy Variable resistors A1R19 and A2R21 are used to calibrate the positive and negative current references SECTION V MAINTENANCE 5 1 INTRODUCTION 5 98 Before returning the BPS A to normal operation re peat the performance check to ensure that the fault has been 5 2 The performance checks Paragraph 5 5 should be properly corrected and that no other faults exist Before made to check the operation of the BPS A after repairs or performing any maintenance checks turn on the BPS A and for periodic maintenance These checks are also suitable for allow a half hour warm up incoming inspection If a fault is detected in the BPS A while making the performance check or during normal oper 5 3 TEST EQUIPMENT REQUIRED ation proceed to the troubleshooting procedures Paragraph 5 60 After repair and replacement Paragraph 5 84 per 5 4 Table 5 1 lists the test equipment required to per form any necessary adjustments and calibrations Paragraph form the various procedures described in this section Table 5 1 Test Equipment Required REQUIRED RECOMMENDED Differential Sensitivity 500uV full scale Measure dc voltages calibration HP345013 with Voitmeter min procedures Measure amplifier Option 001 Input impe
102. is connected to the LO OUT line via R60 However the 20V filtered supply voltage is present for some time causing A3O4 and A305 to be forward biased This drives transistors A3Q2 and A3Q3 into full conduction drawing current away from the bases of A3Q12 and A3013 respectively effectively turning these stages off during the decay of stored voltages 4 38 Meter Circuits The meter circuits provide contin uous indications of output voltage and current VOLTAGE METER M1 is connected across the BPS A output and can be used to monitor ac or dc output voltage depending upon the position of switch A1S1 With A151 in the AC position diode A1CR20 rectifies the ac output voltage in order to obtain an rms reading Variable resistors A1R8 dc adjust and A1R13 ac adjust are used when calibrating the volt meter CURRENT METER M2 is connected across the cur rent sampling resistor A2R27 whose voltage drop is propor tional to the output current Meter M2 can measure ac or dc output current depending upon the position of switch A1S2 With A1S2 in the ac position current meter driver A2U5 and diode CR18 amplify and rectify the ac input applied through C13 in order to obtain an rms reading Variable resistors A1R20 dc adjust and A1R18 ac adjust are used when calibrating the ammeter 4 39 Each meter switch provides two ranges with a 10 1 ratio for each of the dc and ac functions Resistor R54 is a thermistor which in conjunction with R55 com pe
103. is connected to the grounded input terminal of the oscilloscope When using shielded two wire it is essential for the shield to be connected to ground at one end only so that no ground current will flow through this shield thus inducing a noise signal in the shielded leads 5 23 To verify that the osciiloscope is not displaying ripple that is induced in the leads or picked up from the grounds the scope lead should be shorted to the scope lead at the power supply terminals The ripple value obtained when the leads are shorted should be subtracted from the actual rippie measurement 5 24 in most cases the single ended scope method of Figure 5 2B will be adequate to eliminate non real compon ents of ripple and noise so that a satisfactory measurement may be obtained However in more stubborn cases it may be necessary to use a differential scope with floating input as shown in Figure 5 2C 1f desired two single conductor shielded cables may be substituted in place of the shielded two wire cable with equal success Because of its common mode rejection a differential oscilloscope displays only the difference in signal between its two vertical input terminals thus ignoring the effects of any common mode signal intro duced because of the difference in the ac potential between the power supply case and scope case Before using a differ ential input scope in this manner however it is imperative that the common mode rejection capab
104. ise time of the transient is displayed k Starting from the major graticule division repre sentative of time zero count to the right 100usec and verti cally 20mV Recovery should be within these tolerances as illustrated in Figure 5 5 Bou UNLOADING TRANSIENT NOMINAL OUTPUT VOLTAGE LOADING TRANSIENT D TIME iQOuSEC HOMIN AL TM U OUTPUT VOLTAGE UNLOADING TRANSIENT LOADING TRANSIENT Figure 5 5 Transient Recovery Time Waveforms Eg rms voltage across power supply output HPBO terminals BPS A UNDER TEST OSCILLOSCOPE R 1000 Hi QUT O Ein 10 volts g The output impedance should be less than 5 milliohm ZQY crt wm en rm m Figure 5 6 Programming Speed Test Setup 5 33 Programming Speed To check the unit s program ming speed a square wave is applied to the unit and it is op erated in the amplifier mode This has the same effect as rapidly programming the unit up and down in the power supply mode To make this test proceed as follows a Connect test setup as shown in Figure 5 6 b Set MODE switch to VAR GAIN AMPL Figure 5 7 Typical Programming Speed Waveforms RANGE switch to X4 and turn unit on c Rotate VOLTAGE control fully clockwise d On function generator set input frequency to about 100Hz squarewave and adjust amplitude to obtain VOLTMETER VOLTMETER maximum rated peak to peak output signal on oscilloscope UNDICATES o INDICATES EIN 20V to 20V
105. ither a nominal 120 voit or 240 volt 48 63Hz power source A two position selector switch 4 located with in the ac power module on the rear panel selects the power source Before connect ng the instrument to the power source check that the selector switch setting matches the nominal line voltage of the source If required move the witch to the other position Note that the power cable must be removed the plastic door on the power module must be moved aside the fuse extractor must be pulled out ward and the fuse must be removed in order to gain access to the selector switch 2 19 When the instrument leaves the factory the proper fuse is installed for 115 volt operation An envelope con taining a fuse for 230 volt operation is attached to the instru ment Make sure that the correct fuse is installed if the 2 2 2 22 position of the slide switch is changed 2A for 115 volt op eration and 1A for 230 volt operation 2 20 POWER CABLE 2 21 To protect operating personnel the National Elec trical Manufacturers Association NEMA recommends that the instrument panel and cabinet be grounded This instru ment is equipped with a three conductor power cable The third conductor is the ground conductor and when the cabie is plugged into an appropriate receptacle the instrument is grounded The offset pin on the power cable s three prong connector is the ground connection To preserve the protection feature when oper
106. its and the output power transistors Q1 Q4 on the heat sink assembly 5 20 5 78 Turn On Off Circuit The turn on off circuit on board A3 can be isolated from the main amplifier driver cir cuits by disconnecting A3CR3 and or A3CRA if the trouble is in the turn on off circuit the output shouid rise to the proper level with the diode s disconnected To check the operation of the turn on off circuit diodes A3CR3 CR4 are connected short the base of A3Q1 to 2 and the sinewave output will drop to 5V p p When the short is removed the output will return to the full sinewave output 5 80 Qvervoltage Protection Circuit The overvoltage protection clamping diodes are another potential trouble area Diodes A3VR1 and VR2 can be lifted disconnected individually or together while observing the amplifier out put If one or more are shorted the complete sinewave will be restored when the defective diode is disconnected 5 81 Overcurrent Protection Circuit Protection against overcurrent during the transition from constant voltage to constant current operation is provided by diode A3CR22 on the negative output and diodes A3CR20 and CR21 on the positive output If these diodes are defective the output will be badly clipped or the output level will be much lower than normal 5 82 DEGRADED PERFORMANCE PROBLEMS 5 83 Table 5 4 contains a list of less common troubles and their probable causes The troubles in this table are less cat
107. lemented by connecting the proper resistances between A13 A14 strapped together and A18 for positive currents and between A20 A21 strapped together and A18 for negative currents Another method of control of the current is through voltage pro gramming via terminals A14 and A18 and A20 and A18 for positive and negative currents respectively 4 54 A fixed reference current is applied to the other input pin 2 of A2U3 During constant voltage operation A2U3 is saturated causing the output to be positive Zener diode A2VR5 and diode A2CR5 clamp the output at 7 5V preventing A2U3 from going too far into saturation For this condition diode A2CR 14 is back biased and PNP switching transistor A2Q5 is turned off causing A2CR9 and A2CR10 to be forward biased With A2CR 14 back biased constant voltage operation is enabled and constant current operation is disabled the negative constant current diode A2CR13 must also be back biased for this condition With A2CR9 forward biased transistor A101 is turned on allow ing capacitor A2C9 to charge during constant voltage oper ation This will speed up the transition from constant voit 48 age to constant current operation With A2CR10 forward biased the CURRENT MODE indicator DS1 is otf A202 turned on and A2Q3 turned off and the FLAG output is disabled low level FLAG output with A204 turned on Networks consisting of A2C11 R63 R64 and A2C12 R65 R66 are included in the inputs of A2U3
108. lockwise e Turn on BPS A and allow a 10 minute warmup f While switching the RANGE switch between the X1 and X4 positions adjust A2R60 until the X4 reading on DVM is of the same polarity and 4 times the X1 reading within 2 5mV For example if X1 reading is 1mV adjust A2R80 for 2 9mV or less g Set RANGE switch to X1 and adjust A2R61 for OV 0 25mV reading on DVM h Set RANGE switch to X4 DVM should read OV x 1 0mV If not repeat steps f through igi i Remove short from Hl and LO IN terminals 5 104 Constant Voltage Programming Accuracy a Set MODE switch to POWER SUPPLY position and RANGE switch to X1 position b Short terminals A9 and A10 on rear terminal strip c Adjust potentiometers A2R58 coarse and A2R59 fine for a DVM reading of 5 120V 2mV d Turn BPS A off Remove jumper between terminals AB and A9 and connect a precision 10 24K82 5 0596 resistor between terminals A9 and A10 e Turn BPS A on and adjust front panel V ZERO ADJ A1R1 for OV 2mV f Set RANGE switch to X4 position DVM should read OV 8mV If not check A2R60 adjustment step f of Paragraph 5 103 g Turn BPS A off Remove 10 24K82 resistor and connect a 20 48K 0 05 resistor between terminals A9 and A10 h Turn BPS A on DVM should read 20 48V 10mV 5 105 DC Voltmeter Calibration a Set VOLTAGE METER switch to the 24V DC position b Adjust A1R8 for 20 48V indication on BPS A s front panel voltmeter e C
109. lored or charred components 7 M steps 1 through 6 have not isolated the trouble check the supply voltages Paragraph 5 67 5 67 Supply Voltage Checks In almost all cases the trouble can be caused by an incorrect supply voltage main bias or reference voltage thus it is a good practice to check these voltages see Tabie 5 2 Although isolation of the troubie source to a particular board is desireable poss ible trouble in one of the internal power sources should be investigated first The tests described in Table 5 2 consti tute a relatively fast check for trouble in this area In many cases these checks can save many hours of troubleshooting circuits which are actually operating properly If the sup ply voltage checks have not isolated the trouble proceed according to the overall trouble isolation guide Paragraph 5 68 NOTE There are two separate supply voltage re turns in the BPS A designated 7 and in addition to chassis ground When making voltage or waveform meas urements be sure to use the appropriate return The DVM or oscilloscope used must have a floating input since the Q and L I returns are not at chassis ground Tabie 5 2 Main Supply Bios Supply and Reference Voltages METER POSITIVE NORMAL READING CHECK IF NOT CORRECT 35 1 5Vdc A1C7 C9 C10 CR12 CR13 R5 35 1 5Vdc A1C11 C12 C15 CR14 CR15 R6 45 2Vdc 45 2Vdc Bias Supply Voltages TPS 15 BVdc o 1
110. ltage and Current Control Circuits schematic make the following changes Under A2 Voltage and Current Control Plug In Board Delete CR9 diode HP P N 1901 0460 Q1 transistor HP P N 1854 0071 Change R74 to 5 11 k 1 1 8 W HP P N 0757 0438 Make above changes in Current Comparison Amplifier Circuit the on schematic diagram ERRATA In the Replaceable Parts Table under Front Panel Mechanical change part number of clip quantity h to 1400 0547 These changes affect the current meter c cuit on the Ai board Correct the parts list and Sheet 1 of the Figure 7 2 schematic as follows Change A1R 1 to 2 4 k ohm HP P N 0698 1435 the value of A1R21 must be selec ted for optimum performance Change A1R22 to 100 ohm HP P N 0757 0401 Delete AiR19 Replace the DC ammeter calibration procedure of paragraph 5 108 with the following a Turn off BPS A Remove the 10 24 k ohm resistors and replace the jumpers from A20 to A21 and from 413 to AL4 Ensure that jumpers are also from A12 to A13 and from A19 to A21 Adjust the CURRENT control for an output of 0 20 A b Set the CURRENT meter switch to 0 24 A DC position c Adjust AIR20 for a front panel ammeter indication of 0 20A CHANGE 3 In replaceable parts list under AL Interconnect and Power Supply Board Mechanical add heat dissipator qty 4 CR12 CR15 HP P N 1205 0030 k MANERE ain I ds iR amp wA al CHANGE h pin the Replaceable parts table make
111. m to prevent the slave re verting to constant current operation this could occur if the master output current setting exceeded the slave s For equal current sharing the leads from RM to the load and to the terminals should be approximately equal in length To maintain instrument accuracy and stability RM should be a stable low temperature coefficient resistor of sufficient rating to prevent any appreciable self heating typically 182 8W 20 ppm C 190 3 62 BIPOLAR OVERVOLTAGE AND OVERCURRENT LIMIT 3 63 Bipolar overvoltage and overcurrent limit circuits prevent excessive BPS A voltage or current outputs The voltage limiting circuit prevents the output voltage from ex ceeding approximately 22 volts The current limiting cir cuit limits the transient output current to a value approxi mately two times the maximum rated output of 2 0A 3 11 MASTER POWER SUPPLY OR VARIABLE GAIN AMPL MODE LOCAL AUTO SWITCH IN LOCAL AB AS AIC All AIS AIS Ald eigieiejeime LJ mm dees AIS AIG AIT Am AI9 A20 Az M LJ LJ Ry SLAVE FIXED GAIN AMPL MODE LOCAL AUTO SWITCH ih AUTO 2121212121214 wr we AB A9 Bid Ali AI2 AIS Ai4 2121 2121 91219 LJ Zi BB AIG AIT AB AID AZO A2 e ejeleie e ens bond SLAVE 2 FIXED GAIN AMPL MODE LOCAL AUTO SWITCH IN AUTO AB A9 AIG All M2 AS Als oi loeoleleleal ms ZK Ai M6 AIT AIB AIS AZO A21 ejeje eie el C Figure 3 13 Auto Paraliel Connect
112. mming is not applicable in the power supply mode w Jeaigaigl A8 AS AIO AH Al2 AIS AIS glelelelgigi AIS AIG AIT AIB AIS A2O AZI elelolelalgie Figure 3 7 Remote Voltage Programming Constant Voltage 3 50 Variable Gain Amplifier AC signals or a dc level positive or negative can be amplified or attenuated in the variable gain amplifier mode Figure 3 7 shows a variable dc level programming voltage applied to the input termin als A1 HI IN and A2 LO IN Since the BPS A is non inverting in the variable gain amplifier mode a positive input A1 positive A2 negative resuits in a positive output and a negative input A1 negative A2 positive results in a nega tive output The other connections on Figure 3 7 are shown for local control using front panel controls however remote contro using external controls may also be employed The front panel or remote voltage controls can be used to atten uate or amplify the input as required With the front panel VOLTAGE contro or remote programming resistor set for maximum output the programming coefficient is as follows High Range X4 8 volts volt 1 Low Range X1 2 volts volt 196 3 51 Fixed Gain Amplifier AC signals up to 40kHz or a dc level positive or negative can be amplified in the fixed gain amplifier mode Figure 3 7 shows a variable dc level programming voltage applied to the HI A1 and LO A2 input terminals Since the BPS A p
113. mp 510 5 W Not Assigned fxd comp 3K 5 AW fxd comp 1K 5 YW fxd comp 1 2K 5 W fxd comp 8 2K 5 aW fxd comp 750 5 YW fxd comp 6 2K 5 WW txd comp 8 2K 5 aW fxd comp 1 2K 5 SW fxd comp 8 2K 5 GW fxd comp 5 1K 5 4W fxd comp 8 2K 5 W txd comp 750 5 4W fxd comp 1K 5 VW fxd comp 10K 596 2W Not Assigned fxd comp 5 1K 5 WW fxd comp 1 5K 5 AW fxd comp 5 1K 5 W fxd comp 5 6K 5 ZW fxd comp 100 5 W fxd comp 5 3K 5 AW fxd comp 1 6K 5 W fxd comp 18K 5 VW fxd comp 62 5 WAN txd comp 200 5 ZW Table 6 4 Replaceabie Parts HP MFR P 6 9 292P47352 PTS C023B501J2032825 C0238 102G502ZS31 CDH 1N4148 1N4157 1N4148 1N4148 2N4141 40346 J5099 2N4141 SJ5099 40346 40346 SJ5099 40346 J5099 EB 1535 EB 5115 EB 3025 EB 1025 EB 1225 EB 8225 EB 7515 EB 6225 EB 8225 EB 1225 EB 8225 EB 5125 EB 8225 EB 7515 EB 1025 EB 1035 EB 5125 EB 1525 EB 5125 EB 5625 EB 1015 EB 4325 EB 1625 EB 1835 EB 6205 EB 2015 0160 0138 0160 0468 0160 0899 1901 0050 1901 0460 1901 0050 1901 0050 1901 0518 1854 0071 1854 0095 1853 0038 1854 0071 1853 0038 1854 0095 1853 0037 1854 0095 1853 0038 1854 0095 1853 0038 0686 1535 0686 5115 0686 3025 0686 1025 0686 1225 0686 8225 0686 7515 0686 6225 0686 8225 0686 1225 0686 8225 0686 5125 0686 8225 0686 7515 0686 10
114. mplifier mode VOLTAGE control fully clockwise voltage coefficient Voltage X1 Range 2 voits volt t 196 POWER AMPLIFIER SPECIFICATIONS PONERAMPLIHERSPECIFICATIONS Yor a Ranga To Output Voltage X1 Range 10V p p Voltage X4 Range 40V p p Current 2A peak Constant Current voltage coefficient the following applies to variable gain amplifier fixed gain amplifier and power supply modes of operation 2 amperes volt 5 1 3 1 14 OPTIONS 1 15 Options are customer requested factory modifica tions of a standard instrument The option described below applies to Mode 6825A Option No Description 007 Ten turn Output Voltage Control Replaces standard single turn voltage contro to allow greater resolution in setting the output volt age of supply 1 16 ACCESSORIES 1 17 The accessories listed in the following chart may be ordered with the instrument or separately from your local Hewlett Packard sales office refer to list at rear of manual for addresses HP PartNo Descritpion 5060 8762 Dual Rack Adapter Kit for rack mounting one or two supplies in standard 19 inch rack 5060 8760 Blank Panel Filler panel to block unused half of rack when mounting only one supply 11057A Carrying handle easily attached for portabil ity and handling convenience 1052A Combining Case for mounting one or two units in standard 19 inch rack 5060 0789 Cooling kit for above combining case 115 Vac 50 60H
115. n be operated as a power supply or as an amplifier Terminals on the rear terminal strip permit access to various internal control points to further expand the operational capabilities of the unit The resulting flexibility lends the BPS A to an almost unlimited number of applications Some of these applications are outlined in Section Hl of this manual The following paragraphs describe some of the features of the BPS A as a power supply and as an amplifier 1 3 POWER SUPPLY FEATURES 1 4 The unit can be made to function as a regulated dc power supp y by setting the front panel MODE switch to the POWER SUPPLY position The supply can furnish either a Constant Voltage output or Constant Current out put The dc output is bipolar and is continuously adjustable from its maximum rated positive value to an equal negative continuously through zero A crossover feature automati cally changes the supply from constant voltage to constant current operation at a preset or programmed voltage current point The front pane CURRENT MODE indicator lights for constant current operation Both the supply and the load are protected against overvoltage and overcurrent conditions by internal circuits Dual output voltage ranges are provided for better resolution The front panel RANGE switch allows selection of the high X4 or low X1 output range 1 5 The output voltage can be programmed locally using the front panel VOLTAGE control or remotely by means
116. n BPS A and allow a five minute warm up period e Connect oscilloscope to S and S terminals f Adjust VOLTAGE control to obtain a 4V p p reading on the oscilloscope g Observe that front panel voltmeter reads 1 4V rms and the front panel ammeter reads 56A rms h Turn off BPS A and connect appropriate high range load resistor Set RANGE switch to X4 and VOLT AGE METER switch to high range AC Increase generator output to 5V p p i Turn on BPS A and observe oscilloscope for a 40V p p signal j Observe that front panel voltmeter reads 14V rms and front panel ammeter reads 1 4A rms k Set MODE switch to FXD GAIN AMP MODE and increase generator output to 10V p p Observe a 40V p p signal on oscilloscope BPS A UNDER TEST Rs CURRENT SAMPLING RESISTOR FUNCTION GENERATOR HP 3310 HP 33IA DISTORT ION LY ANALYZER O 0 HP 80 OSCILLOSCOPE Ry OHMS HL RANGE LO RANGE NEJBB IGE ME 0 A O DVM AC Figure 5 16 Amplifier Mode Test Setup 5 12 5 58 Frequency Response To check amplifier mode frequency response proceed as follows a Connect the test setup as shown in Figure 5 16 b Set MODE switch to VAR GAIN AMP and set VOLTAGE and CURRENT controls fully clockwise c Set HP3310A generator output at 100Hz sine wave and adjust signal amplitude to provide 40V p p output d Adjust the generator frequency unti output drops to 27V p p This frequency should not be less than
117. n be used as an incoming in spection check and appropriate portions of the test can be repeated either to check the operation of the instrument after repairs or for periodic maintenance terts The tests are performed using a 115Vac 60Hz single phase input power source 5 7 POWER SUPPLY MODE TESTS 5 8 All measuring devices must be connected to the rear sensing terminals of the supply and not to the front output terminals if maximum accuracy is to be obtained in the following measurements In addition the measuring devices must be connected as close to the sensing terminals as possible This is particularly important when measuring the transient response regulation or ripple of the power supply Note that under no circumstances should the meas uring instruments be connected across the load A measure ment made across the ioad includes the impedance of the leads to the load and such lead lengths can easily have an impedance several orders of magnitude greater than the sup ply impedance thus invalidating the measurement 5 9 To avoid mutual coupling effects each monitoring device must be connected to the sensing terminals by a sep arate pair of leads Twisted pairs or shielded two wire cables shouid be used to avoid pickup on the measuring leads The load resistor should be connected across the output termin ais as close to the supply as possible When measuring the constant voltage performance specifications the current con trois sho
118. nals turn on supply and adjust VOLTAGE control for desired output voltage b Short output terminals and adjust CURRENT con trol for maximum output current allowable current limit as determined by load conditions and voltage range selected in step a If a load change takes place and causes the out put current to exceed this setting the power supply will automatically crossover to constant current mode and out put current will be constant at the level set by the CURRENT control The CURRENT MODE indicator will come on and output voltage will drop proportionately to maintain con stant current 3 28 Constant Current To select a constant current output proceed as follows l a Short output terminals and adjust CURRENT con trol for desired output current b Open output terminals and adjust VOLTAGE con trol for maximum output voitage allowable as determined by load conditions and current selected in step a ff a load change causes the voltage to tise the power supply will automatically crossover to constant voltage at the voltage setting and output current will drop proportionately 3 29 OPERATION OF SUPPLY BEYOND RATED OUTPUT 3 30 The shaded area an the front panel meters indicate the amount of output voltage and current that is available in excess of normal rated output Although the BPS A can be operated in this region without damage it cannot be guaranteed to meet all of its performance specifications 3 31 REACTIVE
119. nd hn to 3 mV In paragraph 5 144 change voltage specified in steps k and m to 1 0 mV In paragraph 5 25 step e change the ripple and noise values to X1 Range 3 mV rms 8mV p p X4 Range 10 mV rms 30 mV p p In paragraph 5 27 change data after step e X1 Range 4 mV p p instead of 8 mV p p YH Range 15 mV nen instead of 30 mV nen saai E a Model GU2Z5A Page 2 In paragraph 5 58 change frequency specified in step e to 40 kHz Add step f to paragraph 5 59 as follows f The maximum THD at other frequencies can be measured in similar manner See Table 1 1 for THD percentages i of paragraph 5 107 to read as follows g Momentarily remove the load and adjust front panel IZERO ADJ A1R2 so that the CURRENT MODE light goes out Reconnect load and ad just AIR2 for a DVM reading of 7 to 1 0 mV h Turn VOLTAGE control fully coun terclockwise i Momentarily remove the load and adjust front panel I ZERO ADJ A1R3 so that the CURRENT MODE light goes out Reconnect load and adjust A1R3 for a DVM reading of 7 to 1 0 mV met Change steps a and b of paragraph 5 108 to read as follows a Set CURRENT METER switch to the 2h A DC position AlR20 for a front panel ammeter indication of 2 A Change steps a through c of paragraph 5 111 as follows a Connect DVM across the 1 ohm resistor Set the CURRENT METER switch to the 16 A ac position b Adjust function generator output level for
120. nfinite output impedance by changing the output voltage in response to any load resistance variations Thus it should be noted that the voltage and current comparison amplifiers cannot operate simultaneously For any given value of load resistance the BPS A must act either as a con stant voltage or a constant current supply Transfer between operation is accomplished automatically by switchable de coupling circuits at a value of load resistance equai to the ratio of the output voltage control VOLTAGE control or remote voltage programming control setting and the cur rent control CURRENT control or remote current program ming control setting Figure 4 2 shows the output charac teristics of a constant voltage constant current power sup ply when operated within the bipolar output voltage and current ranges With no load attached Ry sai lout 0 and EQUT ES the front panel voltage or remote program ming control setting When a load resistance is applied to the output terminais of the power supply the output current increases while the output voltage remains constant point D thus represents a typical constant voltage operating point Further decreases in load resistance are accompanied by further increases in IQUT with no change in the output volt age until the output current reaches Ig a value equal to the front panel current or remote programming contro setting At this point the supply automatically changes its mode of op
121. nsates for temperature effects 4 40 VOLTAGE AND CURRENT CONTROL CIRCUITS Figure 7 2 Sheet 2 441 The voltage controi circuits consist of the mode selection voitage reference gain control and voltage com parison circuits The current controi circuits consist of positive and negative current comparison circuits Each of these main circuits and associated components are described in the following paragraphs 4 42 Mode Selection The front panel MODE switch sections A5S2A and A552B allows the selection of the power supply variabie gain amplifier or fixed gain amplif ier operating mode in the power supply mode a positive dc reference voltage is converted to a variable bipolar dc output voltage by operational amplifier techniques in the variable gain amplifier mode an externally applied dc or ac signal is attenuated or amplified by the voltage refer ence gain control circuit for application to the voltage com parison amplifier In the fixed gain amplifier mode the voltage reference gain control circuit is bypassed and an ex ternally applied dc or ac signal is applied directly to the voltage comparison amplifier Each of the above conditions is described in subsequent paragraphs 4 43 Voltage Reference Gain Control Circuit In the power supply mode voltage reference gain control amplifier A2U2 provides a signal 0 to 10V at the junction of A2R6 and A2R7 depending upon the setting of the front pane VOLTAGE control A5R2 or
122. ntrol for reading of 5V on DVM g Set MODE switch to VAR GAIN AMP positive and connect oscilloscope between A2U1 pin 6 TP13 and S h Apply a 100Hz sinewave about 40mV p p to the HI IN A1 and LO IN A2 terminals 1f A2UT is oper ational a sinewave approximately 8V p p should be ob served on oscilloscope If there is no output A2UT or A2K1 is defective ff the output at A2UT pin 6 is t15Vdc A2CR18 CR19 or A2UT is shorted 5 19 5 74 Current Control Circuits integrated circuit ampli fiers A2U3 positive current comparison amplifier and A2U4 negative current comparison amplifier control con stant current operation for positive and negative output currents respectively An OR function results if either circuit is operational and control is established To check these circuits proceed as follows a Remove top and right side covers from instru ment Remove the A3 board b Remove strap between terminals A13 and A14 and apply a small variable dc voltage approximately 0 2 Vdc between terminais A14 and A18 c Connect a DVM between A2U3 pin 6 TP16 and S Turn on power and note that DVM reads from approximately 7V to 8V as the source voltage is varied through zero If voltage reading is correct proceed to step d If reading is 15V check A2U3 for short if reading is zero A2U3 is defective d Turn power off and replace straps between terminals A13 and A14 Remove straps between terminals A2
123. of a resistance connected to the appropriate rear ter minais The output current can be programmed locally us ing the front panel CURRENT control or remotely by means of a resistance or voltage source connected to the appropriate rear terminals The BPS A can be programmed 1 1 controlled at a very high rate of speed less than 5Ousec for output voltage change over the entire voltage span Local and remote programming connections are described in Section IH The output voltage and current ranges are as follows BV to 45V at 0 to 2 0A low range 20V to 20V at 0 to 2 0A high range 1 6 The BPS A can sink as well as source current per mitting it to serve as a variabie load device The BPS A can sink up to 50 of the rated output current 1 7 AMPLIFIER FEATURES 1 8 The unit can be made to function as a variabie gain or a fixed gain amplifier by setting the MODE switch to the VAR GAIN AMP or FXD GAIN AMP position When oper ating as an amplifier the BPS A can amplify externalty ap plied ac or dc signals Variable gain can be controlled local ly VOLTAGE control or remotely and is accurate to 0 1 The variable or fixed gain provided is as follows Variable Gain 0 2 low range 0 8 high range Fixed Gain 1X low range 4X high range 1 9 The variable gain amplifier is non inverting and has a frequency response from dc to 15kHz The fixed gain am plifier is inverting and has a frequency response from dc to
124. of the constant voltage output is not applicable in the FXD GAIN AMP mode of operation The VOLTAGE con troi on the front panel is disconnected disabled for the strapping connections shown in Figure 3 6 To maintain the stability and temperature coefficient of the instrument use programming resistors that have stable low noise and low temperature characteristics less than 20 ppm C Also they should operate at less than 1 30th of their wattage rat ing to minimize short term temperature effects 36 Ai A2 amp S 4 A Rey AIS AIG AIT AIB AI9 A20 AZI TK S Rec REMOTE POSITIVE DC CONTROL VOLTAGE E Ree CURRENT NEGATIVE FLAG X MUST BE ISOLATED FROM CONTROL GROUND Figure 3 6 Remote Resistance Programming Constant Voltage Constant Current NOTE Precision programming resistors 05 resistors must be used 3 43 Power Supply For power supply operation the bipolar output voltage varies linearly from a maximum neg ative value through zero to a maximum positive value accord ing to the value of the programming resistance Rpy The voltage output ranges and correspanding values of Rpy are as follows 6825A ind HIGH LOW RANGE RANGE 0 20 48V 5 12V 10 24KQ OV oy 120 48KN 20 48V 5 12V 3 44 As noted above the output voltage should be zero volts with 10 24K connected to the programming terminals The output may be adjusted to zero by adjusting the V ZERO
125. oltage and the reference voltages 4 47 Voltage Comparison Amplifier Voltage compari son amplifier A2U1 continuously compares the output volt age with a reference voltage The inverting input pin 2 of A2U1 is the summing point which receives a portion of the output voltage feedback voltage from the 4S terminal and the variable reference voltage from A2U2 or from the HI and LO IN terminals A1 and A2 The non inverting input pin 3 of A2UT receives a fixed dc bias If a differ ence exists between these inputs the comparison amplifier produces an error voltage at pin 6 whose amplitude is proportional to the difference The error signal is then app to the series regulator output amplifier via the coupling arr plifier and driver circuits The feedback voltage is applied to the summing point pin 2 of A2U1 from the high sense terminai S via a range network consisting of resistors A A2R16 A2R42 and relay A2K3 Relay A2K3 changes the range of the power amplifier by changing the feed back resistance by a factor of 4 in the X4 range resistor A2R9 A2R16 and A2R42 are in the feedback path In 1 X1 range resistors A2R9 and A2R42 are shorted out Re A2K2 switches in the proper value equalizing network fo each range A2C7 and A2R 14 in the X4 range or these components in parallel with C6 and R15 in the X1 range Relays A2K2 and A2K3 are controlled by the RANGE switch ASS2C positions X1 X4 or REMOTE In the X4 position th
126. onents Div Mountain View Calif Breeze Corporations inc Union N J Reliance Mica Corp Brooklyn NY Sloan Company The Sun Valley Calif Vemaline Products Co inc Wyckoff N J Genera Elect Co Minature Lamp Dept Cleveland Ohio Nylomatic Corp Norrisville Pa RCH Supply Co Vernon Calif Airco Speer Electronic Components Bradford Pa Hewlett Packard Co New Jersey Div Rockaway N J General Elect Co Semiconductor Prod Dept Buffalo N Y Genera Elect Co Semiconductor Prod Dept Auburn NY C 8 K Components Inc Newton Mass Burndy Corp Norwalk Conn Wagner Electric Corp Tung Sol Div Bloomfield N J CTS of Berne Inc Berne Ind Chicago Telephone of Cal Inc So Pasadena Calif IRC Div of TRW inc Boone N C General Instrument Corp Newark N J Philadelphia Handle Co Camden N J U S Terminals inc Cincinnati Ohio Hamlin Inc Lake Mills Wisconsin Clarostat Mfg Co Inc Dover N H Thermafloy Co Dallas Texas Hewlett Packard Co Loveland Colo Cornell Dubilier Electronics Div Federal Pacific Electric Co Newark N J General Instrument Corp Semicon ductor Prod Group Hicksville N Y Fenwal Elect Framingham Mass Corning Glass Works Raleigh N C Table 6 3 Code List of Manufacturers CODE MANUFACTURER ADDRESS Deico Radio Div of Genera Motors Corp Kokomo tnd Atlantic Semiconductors Inc Asbury Park
127. onnect short across 20 48K22 0 05 resistor A9 to A10 Front panel voltmeter should read 20 48V d Turn BPS A off remove 20 48K resistor install jumper between AB and A9 remove DVM from output ter minals and replace top cover 5 106 CONSTANT CURRENT CALIBRATION NOTE The CURRENT MODE light should be on dur ing these procedures 5 107 Constant Current Programming Accuracy a Remove top cover to gain access to potentio meters on boards Al and A2 b Remove jumpers from A19 to A20 and from A12 to A13 on rear terminal strip Short terminals A18 and A13 and A18 to A20 on rear terminal strip d Connect a 182 1 precision resistor Rs in series with the appropriate high range load resistor IRC 4982 6826A or 19902 6827A as shown in Figure 5 16 Connect the DVM across the 182 resistor e Turn on BPS A and allow a 30 minute warmup f Set MODE switch to POWER SUPPLY Set the RANGE switch to X10 and turn the VOLTAGE control fully clockwise g Adjust front panel 1 ZERO ADJ A1R2 for a reading of 0 000 t 3mV on DVM h Turn VOLTAGE control fully counterclockwise i Adjust front panel I ZERO ADJ ATR3 fora reading of 0 000 3mV on DVM NOTE The A1R2 and A1R3 adjustments may interact Repeat steps f through i several times to min imize errors L Turn BPS A off and remove jumper from A18 to A20 Connect a precision 10 24K 0 5 resistor be tween A18 and A20 k Turn VOLTAGE control
128. or combining BPS A s for series and parallel oper ations These connections are employed whenever it is re quired to extend the voltage gain or current capability be yond one supply For series operation the total output voltage gain is the sum of the voltages gains of the individ ual supplies For parallel operation the tota output current is the sum of the output current from the individual supplies For series or parallel operation the BPS A s must be opera ted in the same mode power supply variable gain amplifier or fixed gain amplifier Also each supply must have its Auto Local switch A2S1 see Figure 3 9 in the Local posi tion pushed toward the rear of the instrument Note that the external signal applied to the A1 and A2 terminals is in ternally disconnected when the BPS A s are in the power supply mode 3 55 Series Connections Two or more supplies may be connected in series to obtain a higher voltage gain than is available from a single supply Figure 3 10 illustrates the series connections for three supplies Each of the supplies must be adjusted in order to obtain the desired output voltage gain 3 56 Parallel Connections Parallel operation of BPS A is possible because of the constant voltage constant current crossover feature Two or more power supplies can be con nected in parallel to obtain a total output current greater than that available from one power supply The totai output current is the sum of the outp
129. our i i i I 1 i i d i i I i I I i n i l i i i i I i i i i i l I i DENOTES VOLTAGE FEEDBACK 2 oe DENOTES CURRENT FEEORACK 3 FRONT PANEL VOLTAGE CONTROL OR REMOTE PROGRAMMING RESISTANCE 4 FRONT PANEL CURRENT CONTROL OR REWOTE PROGRAMMING RESISTANCE OR VOLTABEJ Figure 4 1 BPS A Block Diagram 4 1 OVERALL DESCRIPTION ously through zero using the front panel VOLTAGE contro or a remote programming control A crossover feature auto 4 2 GENERAL matically changes the supply mode from constant voltage to constant current Constant voltage CV constant current 4 3 The following paragraphs provide an overall CC operation is described in Paragraph 4 15 The BPS A description of Bipolar Power Supply Amplifier Model is also capable of sinking current that is current from an 6825A The BPS A can be operated as a power supply or a active load can flow back into the BPS A when the output power amplifier As a power supply the BPS A provides a terminal is positive or current can flow out of the output ter precise low noise low drift bipolar output voltage The out mina when the voltage is negative The BPS A can sink cur put voltage can be varied from positive to negative continu rent up to 50 of the rated current output The BPS A can 41 a so function as a variable gain or fixed gain amplifier to am plify externally applied dc and ac signals The variable gain can be controlled
130. ow range DC scale DVM Voltmeter 5V 5V 5V 150mV 5V 150mV 5 11 Source Effect Line Regulation Definition The change AEout in the static value of dc output voltage resulting from a change in ac input voltage over the specified range from low line usually 104 208 volts to high line usualiy 127 254 volts or from high line to low line NOTE The CURRENT MODE light should be off dur ing this test i 5 12 To check the line regulation proceed as follows a Connect the test setup shown in Figure 5 1 Use high range X4 load resistor value b Connect variable auto transformer between the input power source and the BPS A power input c Adjust variable transformer for a 104 volts ac input d Set BPS A front panel controls as follows MODE switch POWER SUPP Y RANGE switch x4 VOLTAGE control midposition CURRENT control fully clockwise VOLTAGE METER high range DC CURRENT METER high range DC e Connect a DVM to the S and S terminals of the BPS A f Turn on BPS A and adjust VOLTAGE control clockwise for maximum rated positive output voltage high range as indicated on DVM g Adjust variable auto transformer for a 127 volts ac input h Reading on DVM should not vary from reading in step f by more than 4mV i Set variable auto transformer for a 104 Vac input j Adjust VOLTAGE control counterclockwise for maximum rated negative high range output voltage as indi c
131. perated up to 300Vdc above ground if neither output ter minal is grounded 3 37 REMOTE SENSING 3 38 Remote sensing is used to maintain good regulation at the load and reduce the degradation of regulation which wouid occur due to the voltage drop in the leads between the power supply and the load Remote sensing is accom plished by utilizing the strapping pattern shown in Figure 3 5 The power supply should be turned off before chang ing strapping patterns The leads from the sensing S terminals to the load will carry much less current than the load leads and it is not required that these leads be as heavy as the load leads However they must be twisted or shielded to minimize noise pickup CAUTION Observe polarity when connecting sense leads to the load eleklo E AL AB A9 AIO All AIS AID AK igieieielel pu A aw AS AIG AI AIB AIS AZCA I 22 2 2112 rf Figure 3 5 Remote Load Sensing 3 39 For reasonable load lead lengths remote sensing limits degradation of the performance of the supply How ever if the load is located a considerable distance from the Supply added precautions must be observed to obtain satis factory operation Notice that the voltage drop in the load leads subtracts directly from the available output voltage Because of this it is recommended that the drop in each load lead not exceed 1 0 volt If a larger drop must be toler ated please consult an HP Sales Engineer NOTE
132. perating Modes M e PA 5 109 AC Meter Calibration COCA 5 24 3 24 Local Programming c ievscsrescssiactecysrsscacecnensseasacesiods dr 3229 Operation of Supply Beyond Rated Qutput 3 5 REPLACEABLE PARTS scccscscssccssessesscssersases sorvsoneresecsers 6 1 3 31 Reactive Load Considerations OCE 3 5 6 1 Introduegnon EEN 6 1 3 33 Connecting Load RGG Nic 3 5 6 3 Ordering Information ees esse eene OFT 3 37 Remote Sensing E PE E 3 5 3 40 Remote Programming seen 3 6 CIRCUIT DIAGRANMS urarannee eren 731 3 53 Series and Parallel Connections e 3 9 7 1 Introduction NORD MEUSE pires Zi 3 57 Auto Series and Auto Parallel Connections 310 73 Simplified Schematic Diagram sss PAT 3 62 Bipolar Overvoltage and Overcurrent Limit 11 75 Component Location Illustrations seseeee 7 1 3 64 Reverse Voltage and Current Loading 11 77 Schematic Diagrams m ee 7 1 SECTION I GENERAL INFORMATION 1 1 DESCRIPTION 1 2 This instruction manual contains operating and service instructions for Bipolar Power Suppl y Amplifier Mode 6825A The Bipolar Power Suppiy Amplifier BPS A is a general purpose instrument useful in any lab oratory engaged in the research and development of elec tronic systems circuitry or components The BPS A ca
133. r toward the rear of the in strument as received from the factory The AUTO position is used for auto series and auto parallel operations see The VOLTAGE METER switch permits mon 3 3 Paragraphs 3 57 through 3 61 The following procedures check both power suppiy and amplifier to ensure that the BPS A is operational POWER SUPPLY CHECKOUT PROCEDURE a Set front panel controls as follows MODE switch 3 POWER SUPPLY RANGE switch 4 X1 VOLTAGE control 5 midposition CURRENT contro 6 full clockwise VOLTAGE METER switch 8 low range DC CURRENT METER switch 10 high range DC b Set LINE switch O to ON and observe that LINE ON indicator 2 lights c Adjust VOLTAGE control from full counter clockwise to full clockwise range through OV and note that maximum output is attained as indicated on meter d Set VOLTAGE METER switch to high range DC and RANGE switch 4 to X4 position e Adjust VOLTAGE control 5 clockwise and counterclockwise through entire bipolar output voltage range through 0 and note that maximum output is attained as indicated on meter 9 Adjust output voltage to 20V f To checkout the constant current circuit first turn off BPS A Short circuit the front panel terminals Hi OUT to LO OUT g Turn on supply and observe that CURRENT MODE indicator e lights and meter indicates near O volts h Adjust CURRENT control 6 from full cw to full cow and note that m
134. rcuit defective A2Q3 shorted c Defective negative output power transistor on heat sink assembly Q3 or Q4 defective Defective negative coupling amplifier or driver stages on A3 board A309 010 Q11 opened VR1 shorted Output voltage latched to maxi Amplifier stage on A3 board defective A3Q11 shorted mum negative Negative current comparison amplifier output diode A2CR13 shorted Check reference voltages at TP11 and TP12 and bias voltage at TP5 and TP6 see Table 5 2 b Check circuit components common to positive A2U3 and negative A2U4 comparison amplifiers Dua ganged CURRENT control A5R2 Speed up network A2C9 Q1 R27 R46 R47 Check positive reference voltage at TP11 see Table 5 2 No constant current operation No positive constant current op eration negative constant current circuits operate properly b Positive current comparison amplifier A2U3 defective see Paragraph 5 71 c A2CR5 CR14 or VR5 defective No negative constant current a Check negative reference voltage at TP12 see Table 5 2 operation positive constant cur rent circuits operate properly b Negative current comparison amplifier A2U4 defective see Paragraph 5 71 c A2CR13 or VR6 defective Positive constant current circuits PNP switch A205 opened operate properly but CURRENT MODE indicator does not light
135. rised of nega tive voltage coupling amplifier stages Q9 Q11 and negative PNP driver transistors 013 Q17 through Q19 4 33 At zero output voltage both the positive and nega tive driver sections are conducting a small current through diodes CR14 CR15 and CR18 to provide the voltage drop necessary to forward bias Q12 and Q13 simultaneously This eliminates dead spots when the BPS A is programmed through zero 4 5 4 34 Bipolar Overvoltage and Current Limiting Circuits The bipolar overvoltage and current limiting circuits are located on board A3 Zener diodes VR1 and VR2 connec ted in the base circuits of Q12 and Q13 prevent the output voltage from exceeding approximately 22 volts Diodes CR20 CR21 and CR22 form current limiting circuits These diodes monitor the output current flowing through the series regulator output amplifier and limit the transient current to a value approximately 2 times the nominal rated output during the transition from the constant voltage to constant current operation 4 35 Turn On Off Circuit The turn on off circuit is comprised of transistor stages Q1 through Q5 on board A3 and relay K1 on board A1 The purpose of this circuit is to limit turn on off transients which might affect the load To accomplish this the output is clamped at a low level when the BPS A is turned on or off 4 36 Before power is applied to the BPS A relay A1K1 is deenergized connecting the HI OUT to LO OUT
136. rovides an inverted out put in the fixed gain amplifier mode a positive input A1 positive A2 negative results in a negative output and a neg ative input A1 negative A2 positive results in a positive output The front panel or remote programming voltage controls are not applicable in this mode The programming coefficient in the fixed gain amplifier mode is as follows High Range X4 4 volts volt 1 Low Range X1 1 volt volt 29 A2 BOARD 4 THESE SUPPLIES MUST BE ISOLATED FR M POWER GROUND Figure 3 8 Remote Voltage Programming Constant Current LOCAL AUTO SWITCH AUTO POSITION a LOCAL POSITION TOWARD FRONT TOWARD REAR Figure 3 9 Local Auto Switch 3 8 3 52 Voltage Programming Constant Current Voltage programming of the output current can be accomplished in all three operating modes power supply variable gain am plifier and fixed gain amplifier Positive and negative dc programming voltages are connected to terminals A14 and A21 respectively as shown in Figure 3 8 The positive or negative output current will vary linearly with changes in the programming voltages The output current varies at a rate determined by the programming coefficient The pro gramming coefficient is 2 amps 1 voit The maximum rated output current is 2A therefore the maximum programming voltage is 1 volt 3 53 SERIES AND PARALLEL CONNECTIONS 3 54 The following paragraphs describe the connections required f
137. s 4 7 The amplifier and driver circuits receive an error signal from the voltage or current comparison amplifiers in order to contral the conduction of the series regu ator output amplifier transistors A positive or negative going error signal is amplified by the appropriate amplifier and driver transistors positive or negative and then fed back to control the appropriate series regulator output amplifier transistors 4 8 During constant voltage operation the voltage com parison amplifier compares a portion of the output voltage feedback with a reference voltage In the power supply or variable gain amplifier mode the reference voltage is re ceived from the reference gain control circuit In the fixed gain amplifier mode the reference voltage is an externally applied ac or dc signal If the feedback and reference volt ages are not equal the voltage comparison amplifier pro duces an amplified error signal which is further amplified by the low level amplifier and driver circuits and then fed to the series regulator output amplifier to contro the out put in this manner the voltage comparison amplifier main 42 tains a constant output voltage and also generates the signal necessary to set the output level according to the reference voltage or the externally applied ac or dc signa Note that the output voltage feedback signal is applied to the voltage comparison amplifier via a range control circuit This circuit provides
138. s from affecting the output voltage The AUTO LOCAL switch A2S1 in the feedback loop is normally left in the LOCAL position The AUTO position is used for auto series or auto parallel operation when the summing junction of the error amplifier must be available for external error signal connections from other units 449 Output Voltage Gain Control Summary As stated previously the BPS A output voltage is developed utilizing operational amplifier techniques in the power supply mode the bipolar output characteristic is developed through the summing of the internal fixed reference voltage VRE El and a voltage which is dependent only on a single programming contro VOLTAGE control ABR2 or a remote program ming resistance EQ is given by the following equations for the X1 and X4 ranges R EQ VREF PV x Re Re V Le A1R42 REE A2R6 A2R7 where Rpy 0 to 20 48KQ front panel VOLTAGE con trol or remote programming resistance Rp feedback resistance A2R16 or A2R9 A2R 16 A2R42 10 24KQ or 40 96KQ X1 or X4 range respectively A1R42 A2R6 A2R7 10 24K Q2 VREF 5 12V 4 7 in the X1 range R EQ 5 12V PL x 128K _ 5 poy 10 245 10 24K 10 24K 10 24K EQ 5 12V PV Au 10 24K therefore EQ 5 12V if Rpy 0 Eg 0 if Rpy 10 24K Eo 5 12V if Rpy 20 48K In the X4 range R E Ee EE 10 24K 10 24K 10 24K 4R EQ 5 12V PY 4 10 24K therefore Eg 20 48V if Rpy 0
139. se Definition The residual AC voltage which is superimposed on the DC output of a reg ulated power supply Ripple and noise may be specified and measured in terms of its RMS or preferably peak to peak value 5 16 Ripple and noise measurement can be made at any input AC line voltage combined with any DC output voltage and load current within rating 5 17 The amount of ripp e and noise that is present on the power supply output is measured either in terms of the RMS or preferably peak to peak value The peak to peak measurement is particularly important for applications where noise spikes could be detrimental to a sensitive load such as logic circuitry The RMS measurement is not an ideal representation of the noise since fairly high output noise spikes of short duration could be present in the ripple and not appreciably increase the RMS value 18 The technique used to measure high frequency noise or spikes on the output of a power supply is more critical than the low frequency ripple and noise measure ment technique therefore the former is discussed separately in Paragraph 5 26 5 19 Ripple and Noise Measurements Figure 5 2A shows an incorrect method of measuring p p ripple Note that a continuous ground loop exists from the third wire of the input power cord of the supply to the third wire of the input power cord of the oscilloscope via the grounded power supply case the wire between the negative output terminal of
140. se assemblies proceed as follows a Remove the rear foot assembly on bottom of the unit by pushing the release button in the center of the foot assembly and sliding the assembly OFF as indicated b Remove bottom cover Paragraph 5 87 The bottom cover is removed to gain access to the A1 board Table 5 5 Semiconductor Replacement Data Reference Designation HP Part No Commercia Replacement Alternative om LL wegen ms A1CR1 CR4 A3CR1 CR7 A2CR1 CR2 CRS psom me CR10 CR13 CR14 CR18 CR24 A3CR15 CR17 1901 0050 1N4148 A3CR19 CR21 om m gt gt 3 Wee n oom Foo ens ne 3 ame EE AtcR1215 _ o morone maaa O oo o o BEE RENE IINE rng T mouse TI Amo sesso anme A102 A201 02 03 4 06 A301 04 06 Im mamn Aa 000000 LL 189494 ams oes ess mu am emeng wewn wes szoa cre cn CRA GRN GR we ee mes E amus E ear News l awmeye 9020064 eme me Moon mee wee sous RA EE Reeg A303 Q6 Q13 Q17 018 Q19 1853 0038 SJ5099 Motorola NOTE 5 32 REAR HEAT SINK ASSEMBLY The release button on the front foot assembly is 5 93 In order to remove the power transistors from the located directly beneath the I ZERO ADJ pot heat sink the rear panels must first be removed After the entiometer on board A1 By pressing slightly in rear panels are removed the transistors are expo
141. sed and can ward on the Al board sufficient clearance is pro be removed Notice that if a new power transistor is in vided to remove the front foot assembly stalled be sure to apply silicon grease Dow DC 5 HP 8500 0059 to both sides of the transistor s mica insulator to c Remove the front foot assembly as in step a assure proper heat exchange except also apply slight inward pressure to the A1 board d Remove one of the side castings Paragraph 5 89 to allow removal of the tilt stand e Remove tilt stand 5 34 Rear Panels To remove the rear panel containing f Replace bottom cover if the unit is to be rack the rear terminal boards and the panel containing the power mounted receptacle proceed as described below 5 22 5 95 Terminal Board Panel a Remove top cover Paragraph 5 87 b Remove two screws at top of unit near Service tag c Remove cable W2 from connector J4 on board A1 d Lift the terminal board panel straight up and out 5 96 Power Receptacie Panel a Remove bottom cover Paragraph 5 87 b Remove two screws securing corner of panel c Lift panel straight up and out 5 97 Heat Sink To remove the heat sink proceed as follows a Remove al covers Paragraph 5 86 b Remove terminal board and power receptacle rear panels see above c Remove four screws securing heat sink to side frames d Remove cable W1 from connector J3 on board A1 The heat sink can now be lifted out 5 98
142. sheet numbers on Figure 7 1 correlate the simplified circuits with the circuits on the detailed schematic The simplified schematic is pro vided for ease of understanding and should be referred to in conjunction with the detailed schematic Sheet 1 of Figure 7 2 illustrates the output power amplifier and input power circuits and Sheet 2 illustrates the voltage and current con trol circuits OUTPUT POWER AMPLIFIER CIRCUITS Figure 7 2 Sheet 1 4 21 4 22 AC input AC input power is applied to the chassis mounted power transformer T1 via the power module on the rear of the unit and the LINE ON switch 1 on the front panel The power module contains fuse F1 1A for 115Vac or BA for 230Vac input power and a slide switch for con necting 115 or 230Vac to the primary of the power trans former The power transformer secondary provides the proper magnitude ac inputs to the rectifier filter and to the bias supply i 4 23 Rectifier Filter The rectifier filter circuits con tained on the interconnect and power supply board A1 provide the main dc power outputs These circuits consist of rectifier diodes arranged in full wave center tapped recti fier configurations with associated filter capacitors and bleeder resistors to provide 35 and 45 volt raw dc outputs The front panel LINE ON indicator DS1 is connected across the 35 volt output to indicate when the BPS A is turned on The 35 volt outputs are the main input lines to the s
143. ss of the nearest service office to which the instrument can be shipped Be sure to attach a tag to the instrument speci fying the owner model number full serial number and ser vice required or a brief description of the trouble 2 9 INSTALLATION DATA 2 10 The instrument is shipped ready for bench opera tion It is necessary only to connect the instrument to a source of power and it is ready for operation 2 1 2 11 LOCATION 2 12 This instrument is convection cooled Sufficient space should be allotted so that a free flow of cooling air can reach the top and rear of the instrument when it is in operation It should be used in an area where the ambient temperature remains between O9 C and 550C 2 13 OUTLINE DIAGRAM 2 14 Figure 2 1 illustrates the outline shape and dimen sions of the BPS A TERMINAL STARE TAIL OUTPUT TER AA T 45 E ABAD ADA NZ A344 i tt 096 1279 enl HOKA E230 168254 68264 ETA 0 40600 Sem SA30A 68314 6452A is eas j Vir ima Figure 2 1 Outline Diagram 2 15 RACK MOUNTING 2 16 The BPS A may be rack mounted using either the dual rack adapter kit or the combining case with appropri ate cooling kit described in Paragraph 1 16 The necessary installation instructions are provided with the accessories Refer to Paragraph 5 91 before proceeding with the rack mounting installation instructions 2 17 INPUT POWER REQUIREMENTS 2 18 The BPS A may be operated continuously from e
144. t voltage recovery to within the specified level of the nominal output voltage following a change in output current equal to the current rating of the supply 100usec is required for output voltage recovery within 20mV of nominal output voltage Resolution Typical output voltage or current change that can be obtained using front panel controls Voltage X1 Range 10mV Voltage X4 Range 40mV Current 3mA Output impedance Typical to 50kHz Approximated by a resistance in series with an induc tance constant voltage operation 5mQ amp 1 5uH Tabie 1 1 Specifications Model 6825A Continued POWER SUPPLY SPECIFICATIONS Continued DC Qutput Isolation Supply may be floated at up to 300V above ground Voltage Gain High Low Range Fixed Amplifier Inverting 4X high range 1X low range Variable Gain Non Inverting 0 8 high range 0 2 low range Remote Resistance Programming Resistance Coefficient Voltage X1 Range 20002 V 1 Voltage X4 Range 50022 V t 1 Current BO mA x 1 Frequency Response 1 3dB at full output Fixed Gain de 40kHz Variable Gain dc 15kHz Distortion Total harmonic distortion is 1 maximum at 100Hz and full output Remote Programming Speed SOusec are required to change between 1 and 99 of the maximum and voltage limits Input Impedance 10K amp Typical Remote Programming
145. ternally seiected via the rear terminal strip see Paragraph 3 45 3 2 3 12 VOLTAGE CONTROL 3 13 The VOLTAGE control controls the output level power supply operation or gain variabie gain ampli fier operation of the BPS A in power supply operation the VOLTAGE contro varies the output voltage from a maximum negative value full counterclockwise through zero midposition to a maximum positive value full clock wise n variable gain amplifier operation the gain is vari able from zero to the maximum gain as the VOLTAGE con trol is varied from full counterclockwise to full clockwise In fixed gain amplifier operation the VOLTAGE contro does not contro circuit operation 3 14 CURRENT CONTROL 3 15 The CURRENT control sets the constant current output of the BPS A This control is operable in all three modes of operation power supply variable gain ampli fier and fixed gain amplifier and controls the output cur rent from O to the maximum rated output When the instru ment switches from constant voltage to constant current operation the CURRENT MODE indicator lights Selection of constant voltage or constant current operation is described in Paragraphs 3 27 and 3 28 3 16 VOLTAGE METERING 3 17 itoring the DC or AC output voltage on voltmeter The shaded area on the voltmeter face indicates the amount of output voltage that is available in excess of the normal rated output The voltmeter upper scale reads the b
146. the proper scaling of the output in the high and low output ranges 4 9 in the power supply mode the voltage comparison amplifier and output amplifier amplifiers drivers and series regulator blocks can be viewed as a power operational am plifier whose inputs consist of the feedback signal and a control signal from the reference gain control circuit block The control signal is derived from an internal dc reference voltage which is applied to the reference gain control circuit via the MODE selection switch As the result of a summing action a bipolar output can be obtained whose magnitude and polarity depend only upon the setting of the VOLTAGE contro or remote programming resistance connected across the reference gain control circuit refer to Paragraph 4 43 for a detailed description of this circuit In the vari able gain amplifier mode an external dc or ac signal is applied to the reference gain control circuit via the MODE switch For variable gain amplifier operation the magnitude of the output depends upon the setting of the VOLTAGE Control or remote programming resistance and the polarity of the output is the same polarity as the input signal ln the fixed gain amplifier mode an external ac or de signa is ap plied to the voltage comparison amplifier via the MODE _ switch the reference gain control circuit is bypassed For fixed gain amplifier operation the output signal is inverted The range control circuit in the volta
147. tru ment Figure 7 2 2 Sheets is a detailed schematic of the unit The circled test point numbers on Figure 7 2 are also marked on the component location diagrams which ac company the schematics References are made to these test points in the troubleshooting procedures 5 64 OVERALL TROUBLE ISOLATION PROCEDURE 5 65 Figure 5 17 illustrates the overall scheme of the trouble isolation and troubleshooting procedures which follow The trouble isolation procedures represented by the boxes in the left hand column are intended to localize a problem to a particular area both by direct testing and a process of elimination Instructions at each stage of the iso lation procedure direct you to the appropriate troubleshoot ing instructions if required These steps must be followed in the order in which they are given so that circuits are oper m ational that are needed for testing other circuits It is not THD of Amplifier THD of igen tamp THD me necessary to make any calibration adjustments until trouble shooting has been completed At that time any necessary 5 60 TROUBLESHOOTING WARNING The following troubleshooting procedures are performed with power applied to the 8PS A while its protective covers are re moved Be careful when performing the procedures as line voltage is always pres ent on the power input connector fuse holder and in the power supply rectifier circuits tn addition when the supply is on energ
148. uld be set weil above at least 1096 the maximum output current which the supply will draw since the onset of constant current action will cause a drop in output volt age increased ripple and other performance changes not properiy ascribed to the constant voltage operation of the supply 5 10 DC Voltage Output and Voitmeter Accuracy To check the DC voltage output and voltmeter accuracy pro ceed as follows NOTE The CURRENT MODE light should be off dur ing this test a Connect high range load resistor Ri across output terminals see Figure 5 1 b Connect DVM across S and S terminals c Set BPS A front panel controls as follows MODE switch POWER SUPPLY RANGE switch x4 VOLTAGE control midposition 5 2 DIGITAL OR DIFFERENTIAL VOLTMETER DYM BPS A UNDER TEST Figure 5 1 Power Supply Mode Test Setup CURRENT control fully clockwise VOLTAGE METER high range DC CURRENT METER h gh range DC d Turn on BPS A and allow a five minute warm up period e Turn VOLTAGE control clockwise until DVM indicates 20V f Observe that front panel voltmeter reads 20V 0 6V g Turn VOLTAGE control counterclockwise until DVM indicates 20V h Observe that front pane voltmeter reads 20V 0 6V i Turn off BPS A Change load resistor Ry to low range value see Figure 5 1 and set RANGE switch to X1 j Repeat steps d through h for following DVM and front pane voltmeter readings use l
149. ut currents of the individual power supplies The load must be selected so that the current limit of one supply is exceeded allowing it to operate in the constant current mode The output CURRENT controls of each power supply can be separately set The output voltage controls of one power supply should be set to the desired output voltage the other power supply should be set for a slightly larger output voltage The supply set to the lower output voltage will act as a constant voltage source the supply set to the higher output will act as a constant current source dropping its output voltage until it equals that of the 3 9 A2 de Al BPS A NO t AB A9 AIDAN AR AIS Aa Vieleieiggle bocsa r AIS AIG AT AIS AIS AZ A21 ejejojo 4 4 9 4 BPS A NO 2 AB A9 AIO Ail AI2 AIS Al4 elelejeiqisigi A HM AIS AIG AIT AiB AIS A20A21 Sebcaz RL BPS A NO 5 ag A9 AO Al AI2 A An oio AIS AIS AT AB AIS A OA2I elealelelalel pop NOTES 4 ALL THREE UNITS MUST BE OPERATED IN THE SAME MODE 2 UNITS 2 AND 3 MUST BE FLOATED NOT CONNECTED TO CHASSIS Figure 3 10 Series Connections other supply The constant voltage source will deliver only that fraction of its total rated output current which is necess ary to fulfill the total current demand Figure 3 11 illustrates the parallel connections for three units elalalglglalel A A8 A9 AO All AIZ AIS AIG 9jeleloloje BPS A e 2 90 KIT
150. ut power source and the BPS A power input Adjust variable auto transformer for a 104Vac input c Set BPS A front panel controls as follows MODE switch POWER SUPPLY RANGE switch X4 VOLTAGE control midposition CURRENT control fuliy clockwise VOLTAGE METER high range DC CURRENT METER high range DC d Connect a DVM to the S and S terminals of the BPS A e Turn on BPS A and adjust VOLTAGE control clockwise for the maximum rated positive output voltage as indicated on DVM f Disconnect load resistor Reading on DVM should not vary from the reading in step e by more than 2 5mV g Adjust VOLTAGE control counterclockwise for maximum rated negative output high range as indicated on DVM h Connect load resistor high range value Read ing on DVM should not vary from reading in step g by more than 2 5mV i Turn off BPS A and change load resistor to low range X1 value and RANGE switch to X1 j Turn on BPS A and adjust VOLTAGE control clockwise for the maximum rated positive output voltage low range as indicated on DVM k Disconnect load resistor Reading on DVM should not vary from the reading in step j by more than 0 25mV i Adjust VOLTAGE control counterclockwise for the maximum rated negative output voltage low range as indicated on DVM m Connect load resistor low range value Read ing on DVM should not vary from reading in step e by more than 0 25mV l 5 15 PARD Ripple and Noi
151. voltages or frequencies in excess of those stated on the data piate may cause leakage currents in excess of 5 0 mA peak SAFETY SYMBOLS Instruction manual symbol the product will be marked with this symbol when it is necessary for the user to refer to the instruction manual refer to Table of Contents gt Indicates hazardous voltages Indicate earth ground termina P W The WARNING sign denotes a hazard it calls attention to a procedure practice or the like which if not correctly per formed or adhered to could result in personal injury Do not proceed beyond a WARNING sign until the indicated conditions are fully understood and met WARNING The CAUTION sign denotes a hazard It calis attention to an operating pro cedure or the like which if not correct ly performed or adhered to cou d result in damage to or destruction of part or ail of the product Do not proceed beyond a CAUTION sign until the indicated con ditions are fully understood and met CAUTION DO NOT SUBSTITUTE PARTS OR MODIFY INSTRUMENT Because of the danger of introducing additional hazards do not install substitute parts or perform any unauthorized modification to the instrument Return the instrument to a Hewiett Packard Sales and Service Office for service and repair to ensure that safety features are maintained Instruments which appear damaged or defective should be made inoperative and secured against unintended op
152. ww 20 48K 05 W fxd film 6K 1 1 8W fxd film 100 1 1 8W fxd film 4 75K 1 1 8W fxd film 3K 1 1 8W fxd film 1K 1 1 8W fxd ww 10 24K 05 GW fxd film 1 18K 1 1 8W var ww 10K 5 1W fxd film 57 6K 1 WW var ww 10K 5 1W fxd film 57 6K 1 KW Not Used Jumper fxd comp 3 9 5 WW fxd film 200K 1 1 8W Not Used Jumper fxd ww 0 5 5 DW fxd film 383K 1 1 8W Not Assigned fxd film 9 09K 1 1 8W fxd film 12K 1 1 8W fxd film 2K 1 1 8W fxd film 8 25K 1 1 8W fxd film 21 5 1 1 8W fxd film 8 25K 1 1 8W Table 6 4 Replaceable Parts 6 7 RDM15E300J3S 1N4148 1N485 1N4148 1N485 1N4157 1N4148 1N485 1N4148 1N4148 2N4141 2N2907 2N4141 CEA T 0 R303B CEA T 0 CEA TO 132F CEA T 0 132F CEA T 0 CEA T 0 CEA T 0 CEA T 0 CEA T 0 132F CEA T 0 CT 106 4 CCA T 0 CT 106 4 CCA T 0 EB 39G5 CEA T 0 TIA CEA T 0 CEA T 0 CEA T 0 CEA T 0 CEA T 0 CEA T 0 CEA T 0 ai e HP p EE DESCRIPTION MFR PART NO ar SD 0160 0181 1901 0050 1901 0033 1901 0050 1901 0033 1901 0460 1901 0050 1901 0033 1901 0050 1901 0050 0490 1013 0490 0399 1854 0071 1853 0099 1854 0071 0757 0280 0871 1935 0757 0280 0698 3476 0811 2958 0698 3476 0811 2959 0698 3476 0757 0401 0757 0437 0757 1093 0757 0280 0811 2958 0698 3512 2100 0989 0757 0114 2100 0989 0757 0114 0698 5139 0757 0472 0811 2103 0698 34
153. y available at many points par ticularly the power transistors on the rear heat sink may result in personal injury or death when contacted adjustments should be made and then the performance test of Paragraph 5 5 should be completed CAUTION Trouble isolation by swapping a good board for a suspected faulty one is not recommended un less it is certain that the fault is not destructive 5 66 Preliminary Trouble Isolation Checks Make the following checks for obvious troubles before continuing with the troubleshooting procedures 1 Check that the rear terminal strapping is correct for local or remote programming see Section II CAUTION The rear terminals must be strapped correctly before power is applied to the instrument 5 13 PRELIMINARY TROUBLE ISOLATION CHECK FECTI FOR Se OBVIOUS FAULTS START MAIN POWER FUSE SWITCHES ETC PARAGRAPH 5 66 PARAGRAPH 5 66 REPAIR COMPLETED SATISFACTORY SUPPLY VOLTAGES ON A BOARD AND SUPPLY VOLTAGE REFERENCE VOLTAGES PELE CIE TROUBLESHOOTING ON AS BOARD TABLE 5 2 PARAGRAPH 5 67 REPAIR COMPLETED SATISFACTORY OVERALL TROUBLE ISOLATION GUIDE AND TROUBLE ISOLATED TO BOARD OR COMPONENT BOARD ISOLATION PROCEDURE PARA S 5 68 THRU 5 70 COMPONENT A2 BOARD SAGE Sch TROUBLESHOOTING TROUBLESHOOTING TROUBL SHOOTING TABLE 5 3 IPARAGRAPH 5 71 PARAGRAPH 5 76
154. ypically associated with an incorrect measurement setup 5 51 Ripple Measurement To check the output ripple proceed as follows a Connect the oscilloscope as shown in Figures 5 11B or 511C b Rotate the VOLTAGE control fully cw c Set RANGE switch to X4 MODE switch to POWER SUPPLY and turn on BPS A 5 10 POWER SUPPLY CASE OSCILLOSCOPE CASE A INCORRECT METHOD GROUND CURRENT Tg PRODUCES 60 CYCLE DROP IN NEGATIVE LEAD WHICH ADDS TO THE POWER SUPPLY RIPPLE OISPLAYED ON SCOPE POWER SUPPLY CASE OSCILLOSCOPE CASE TWISTED PAIR LENGTH OF LEAD BETWEEN Ry AND OUTPUT TERMINAL OF POWER SUPPLY MUST BE HELD TO ABSOLUTE MINIMUM B A CORRECT METHOD USING A SINGLE ENDED SCOPE OUTPUT FLOATED TO BREAK GROUND CURRENT LOOP TWISTED PAIR REDUCES STRAY PICKUP ON SCOPE LEADS POWER SUPPLY CASE OSCILLOSCOPE CASE SHIELDED LJ 3 TWO WIRE LENGTH OF LEAD BETWEEN Rr AND GROUNDED OUTPUT TERMINAL OF POWER SUPPLY MUST BE HELD TO ABSOLUTE MINIMUM C A CORRECT METHOD USING A DIFFERENTIAL SCOPE WITH FLOATING INPUT GROUND CURRENT PATH 1S BROKEN COMMON MODE REJECTION OF DIFFERENTIAL INPUT SCOPE IGNORES DIFFERENCE IN GROUND POTENTIAL OF POWER SUPPLY amp SCOPE SHIELOED TWO WIRE FURTHER REDUCES STRAY PICKUP ON SCOPE LEAD Figure 5 11 CC Ripple and Noise Test Setup d Adjust CURRENT contro untii front panel meter reads exactly the maximum rated positive output current e The observed ripple should be less than

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