Home

HP 6525A User's Manual

1. HP PART NO 0686 1225 0686 5125 0686 1825 0686 3925 0686 6205 0686 3325 0686 7515 0812 0010 0686 1055 2100 1824 0656 5125 0689 1025 0686 3315 0686 1035 0686 3325 0686 4725 0686 3625 0686 1525 0686 5115 0686 5105 0812 0097 0686 4715 0686 1025 0686 3325 0686 1025 0686 6815 0698 3629 0686 5615 0686 2735 0686 1225 0686 1515 0686 2025 0686 1835 0698 5503 2100 3210 0686 7525 2100 1823 0689 7515 0689 1025 0686 1535 0686 5125 0686 2235 1902 0049 1902 0777 1902 0049 1902 0785 1902 0049 DESCRIPTION fxd comp 1 2kQ 5 jaw fxd comp 5 1kQ 5 aw fxd comp 1 8kQ 5 aw fxd comp 3 9k0 5 aw NOT ASSIGNED NOT USED NOT ASSIGNED NOT USED NOT ASSIGNED fxd comp 620 15 Vw fxd comp 3 3kQ 2590 jaw fxd comp 7500 5 Yw fxd comp 3 3k Q 2w fxd comp 1 MQ 5 jaw var ww Sk Q 20 fxd comp 5 10 5 jaw fxd comp ik Q 5 iw fxd comp 3300 5 Aw fxd comp 10k2 15 aw fxd comp 3 3kQ 5 aw fxd comp 4 7k 2 5 aw fxd comp 3 6kQ 5 Vw fxd comp 1 5kQ 915 Yaw fxd comp 5109 15 w fxd comp 512 5 aw fxd ww 750 5 Sw fxd comp 4700 15 Yw fxd comp 1kQ 15 aw fxd comp 3 3kO 42590 aw fxd comp 1kQ 5 jaw fxd comp 6800 5 Aw fxd film 2700 5 2w fxd comp 5600 5 Yaw fxd comp 27kQ 5 rw fxd comp 1 2k2 5 Vw NOT ASSIGNED fxd comp 1500 5 Aw fxd comp 2kQ 5 jaw fxd comp 18kQ 5 Aw fxd comp 163MQ 10 4w var comp 10k series 70 10 fxd comp
2. McGraw Edison Co Orange N J Signetics Corp Sunnvvale Calif Bendix Corp The Navigation and Control Div Teterboro N J Electra Midland Corp Mineral Wells Texas Fansteel Metallurgical Corp No Chicago Ili 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 Lamp Div of Con sumer Prod Group Nela Park Cleveland Ohio General Radio Co West Concord Mass LTV Electrosystems Inc Memcor Com ponents Operations Huntington Ind Dynacool Mig Co Inc Saugerties N Y National Semiconductor Corp Santa Clara Calif Hewlett Packard Co Palo Alto Calif Heyman Mfg Co Kenilworth N J IMC Magnetics Corp New Hampshire Div 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 Ill P R Mallory 6 Co Inc i Indianapolis Ind Muter Co Chicago Ill New Departure Hyatt Bearings Div General Motors Corp Sandusky Ohio Ohmite Manufacturing Co Skokie Ill Penn Engr and Mfg Corp Dovlestown Pa Polaroid Corp Cambridge Mass Ravtheon Co Lexington Mass Simpson Electric Co Div of American Gage and Machine Co Chicago Ill Sprague Electric Co North Adams Mass Superior Electric Co Bristol Conn Syntron Div o FMC Corp Homer City Pa Thoma
3. WARNING The CAUTION sign denotes a hazard it calls attention to an operating pro cedure or the like which if not correct ly performed or adhered to could result in damage to or destruction of part or all 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 operation until they can be repaired by qualified service personnel Figure 1 1 Typical High Voltage DC Power Supply iii SECTION 1 GENERAL INFORMATION l i DESCRIPTION 1 2 Hewlett Packard s High Voltage DC Power Supplies Figure 1 1 are all semiconductor compact well regulated constant voltage constant current models suitable for either bench or rack operation A three wire five foot input power cord is provided The output is continuously variable between zero and the maximum rating of the supply The continuously variable current con trol may be used to set the maximum output current overload or short circuit current when the supply is
4. Q13 is the base emitter bias of reference series regulator 014 In response to the error signal the reference series regulator adjusts the 12 4 Vdc so that is remains constant Potentiometer R91 is a line compensation adjustment Zener diode VR3 pro vides bias for Q14 Zener diodes VR2 and VR4 main tain the 6 2 and 9 4 Vdc for the voltage and cur rent programming currents respectively Diode CRS clamps the voltage across R4 R5 when the voltage programming resistance is turned down rapidly If the voltage programming resistance is reduced to zero rapidly R6 would be connected directly to the negative output which might be at 1 000 Vdc R6 limits the programming current 4 54 METER CIRCUIT The ammeter is connected across current monitoring resistor R20 The voltage across R20 is proportional to the output current plus the voltage programming current Resistors R118 and R119 variable calibrate the ammeter The voltmeter is connected across R20 and the power supply output This prevents the voltmeter current from flowing through R20 Resistors R127 and Rii7 variable calibrate the voltmeter R116 drops most of the out put voltage SECTION V MAINTENANCE 5 1 GENERAL during normal operation proceed to the trouble shooting procedures After troubleshooting and 5 2 Table 5 1 lists the type of test equipment repair perform any necessary adjustments and cal its required characteristics use anda recom ibrations B
5. in Table 6 4 give a complete description of the part its function and its location Table 6 1 Reference Designators assembly miscellaneous blower fan electronic part capacitor fuse circuit breaker jack jumper diode relay device signal inductor ing lamp meter 6 1 vw R S m i rm i r i tn Table 5 2 resistor switch transiormer terminal block thermal switch ampere alternating current assembly board bracket degree Centigrade card coefficient composition z cathode rav tube z center tapped direct current z double pole double throw double pole single throw electrolytic encapsulated z farad z degree Farenheit fixed germanium Henrv Hertz integrated circuit inside diameter incandescent kilo 103 milli 1073 mega 106 micro 1076 metal photocell etc zener diode z socket z integrated cir cuit or network Description Abbreviations manufacturer modular or modified mounting mm O nano 107 z normaliv closed normally open nicke l plated ohm order by description outside diameter pico 10 12 printed circuit potentiometer peak to peak parts per million peak reverse voltage rectifier root mean square silicon single pole double throw single pole single throw small signal siow blow tantulum titanium z volt z variable z wir
6. 4 106 kHz to 1 mHz less than 3 ohms AC VOLTMETER amp 4038 INDICATES Eo AC VOLTMETER amp 4038 INDICATES E in POWER SUPPLY UNDER TEST OSCILLATOR Figure 5 3 Output Impedance Test Setup Diagram 5 18 CONSTANT CURRENT OPERATION 5 19 Rated Output and Meter Accuracy Proceed as follows a Connect test setup shown in Figure 5 4 b Turn front panel VOLTAGE controls to maximum rated output c Turn front panel CURRENT control until front panel ammeter indicates 0 20 ampere d The differential voltmeter should indicate 2 0 04 vdc 5 20 line Regulation Proceed as follows a Connect test setup shown in Figure 5 4 b Turn front panel VOLTAGE controls for maximum rated output c Connect the variable voltage transformer between the input power source and the power sup ply power input Adjust the variable voltage trans former to 104 VAC POWER SUPPLY UNDER TEST da DIGITAL VOLTMETER SIEMENS AMERICA INC MODEL B28800 XIO MULTIPLIER RESISTOR FOR VOLTMETER 4 TERMINAL R CURRENT SAMPLING 5 RESISTOR LOAD RESISTOR HIGH VOLTAGE RELAY SUCH AS MAGNECRAFT WISSHVX 1 24v OPERATION OR WISBHVX 2 HOV OPERATION Figure 5 4 Constant Current Test Setup Diagram d Turn front panel CURRENT control until the differential voltmeter indicates 2 0 vdc e Adjust the variable voltage transformer to 127 VAC f Differential voltmeter indication should change by le
7. MODEL RL SK 20K 80K 1 3 td y LOAD SWITCH NOTE 2 NOTES i 1 THIS DRAWING SHOWS A 2 USE MERGURY RELAV CIARE SUGGESTED METHOD OF TYPE HGP 1002 ORW E TYPE 276B BUILDING A LOAD SWITCH 3 USE WIRE WOUND RESISTOR HOWEVER OTHER METHODS COULD BE USED SUCH AS A TRANSISTOR SWITCHING NETWORK MAXIMUM LOAD RATINGS OF LOAD SWITCH ARE AMPS 500V 250W NOT 2500w Figure 5 1 Transient Recovery Time Test Setup 5 14 ADDITIONAL CONSTANT VOLTAGE SPECIFI CATION CHECK 5 15 Temperature Coefficient a Connect the load resistance value shown in Figure 5 1 100 1 voltage divider and the dif ferential voltmeter to the T connector b Turn front panel CURRENT control fully clockwise maximum c Tum front panel VOLTAGE controls until the differential voltmeter indicates maximum rated voltage output d Insert the power supply into the con trolled temperature oven differential voltmeter remains outside oven Set the temperature to 30 C and allow a half hour warm up e Record the differential voltmeter indica tion f Raise the temperature to 400C and allow a half hour warm up g Differential voltmeter indication should change by less than 20 mvdc from indication recorded in step e As 50 SECONDS sio AN 50 MV UNLOADING TRANSIENT TRANSIENT TIME Transient Recovery Waveform Diagram Figure 5 2 5 16 Output Stability Proceed as follows a 5 15 a b
8. aw EB 3335 NOT USED NOT ASSIGNED NOT USED Line Switch NOT USED Power Transformer Auxilary Transformer NOT USED 2BRS53B Thumbwheel Assemblies NOT USED Thumbwheel Assembly see items below marked with Deck 1 L to R H V Board R221 R226 imQ 11 Iw S 203 Switch rotary Deck 2 L to R P C Board R211 219 2000 1 1w S 202 Switch rotary Deck 3 L to R P C Board R201 209 20kQ 1 iw S 201 Switch rotary Deck 4 L to R Pot Board R200 var 20kQ 5 mica insu ator diode mica insulator transistor Transistor Socket Fuse Holder Body Insulator transistor pin Insulating bushing Trim strip extrusion Bushing insulator Tefion Connector receptable H V BNC bulkhead mtg jack rec Strain relief bushing SR 6P3 4 HP PART NO 0370 0084 0510 0123 8120 1348 0180 1973 0160 2589 7200 0084 7200 0085 0380 0703 0380 0706 0380 0145 2100 0565 2100 0569 0380 0701 0340 0175 0340 0452 0340 0415 1251 2357 06522 00004 2515 0003 2580 0005 0360 0621 8150 3078 06525 00004 06525 00016 06525 00015 06525 00019 06525 20007 Kii OL ON A e Lo me me OT me mme met ne ak ed Det fes james DESCRIPTION Knob black 5 8 dia Pilot light fastener Line cord plug PH151 7 ft Capacitor clamp 3 1 6 dia Capacitor clamp footed bkt Captive fastener 6 32 Ext heat sink 4 5 8 ig Ext tee 9 ig Phenolic Spacer Alum spacer Alum spacer Fuse holder carrie
9. non elect 4uf 4k Vdc NOT ASSIGNED fxd elect 1450uf 45 Vdc fxd paper Inf 4k Vdc NOT USED fxd elect 3300uf 200 Vde NOT USED NOT ASSIGNED NOT USED NOT ASSIGNED NOT USED NOT ASSIGNED NOT USED NOT ASSIGNED NOT USED NOT ASSIGNED NOT USED NOT ASSIGNED NOT USED NOT ASSIGNED NOT USED rect Si 500 mA 200prv indicator Light Neon Fuse Cartridge 8A 125V Fuse Cartridge 6A 250V normal blow Choke 780uH 6A Choke 104H 6A Choke 2004H 4A Meter 0 50mA Type 673 S Meter 0 4kV Type 673 S NOT USED NOT ASSIGNED NOT USED var ww 2kQ 5 20ppm NOT USED NOT ASSIGNED NOT USED 56289 28480 56289 56289 56289 56289 03508 91802 75915 75915 28480 28480 28480 28480 28480 28480 268P 10 300164 D39532 300164 32D332F200DE6A 114B 2910821 312008 312006 R40 44 R45 49 R50 32 R53 77 R78 83 R84 111 R112 R113 119 R120 R121 124 R125 R126 R128 132 R133 135 0811 1901 0686 3335 3101 2544 9100 1888 5080 1912 06525 60001 06525 60002 0698 5506 3100 1901 5060 6113 0698 5505 3100 1902 5060 6112 0698 5522 3100 1902 06522 60002 2100 2474 0340 0174 1200 0708 2100 0564 0340 0166 0340 0168 7200 0308 0340 0176 1250 1267 0400 0098 pl OO m EM WG R NO pt tet mes ND ah me ND e me ED A DESCRIPTION NOT ASSIGNED NOT USED NOT ASSIGNED NOT USED NOT ASSIGNED NOT USED 7 NOT ASSIGNED NOT USED fxd ww 402 5 20w NOT USED fxd comp 33kQ 15
10. 7 5k2 5 Yaw var ww 3kQ 20 NOT USED fxd comp 7502 5 lw fxd comp 1kQ 5 1 w fxd comp 15kQ 15 aw fxd comp 51kQ 5 Aw fxd comp 22k9 5 Aw diode zener 6 19 V 5 400 mW diode zener 6 2V 5 400 mW diode zener 16 9 V 5 400 mW diode zener 9 V 0 005 500 mW diode zener 16 9 V 5 400 mW MFR PART NO EB 1225 EB 5125 EB 1825 EB 3925 EB 6205 EB 3325 EB 7515 EB 3325 EB 1055 110 F4 EB 5125 GB 1025 EB 3315 EB 1035 EB 3325 EB 4725 EB 3625 EB 1525 EB 5115 EB 5105 5XM EB 4715 EB 1025 EB 3325 EB 1025 EB 6815 C428 EB 5615 EB 2735 EB 1225 EB 1515 EB 2025 EB 1835 EFQ EB 7525 110 F4 GB 7515 GB 1025 EB 1535 EB 5125 EB 2235 IN753 IN825 IN936 A2 Cl 6 C7 9 C10 Ci C12 13 C14 15 CI6 C17 18 CI9 C20 C21 22 C23 C24 C25 C26 32 C33 34 CRi 4 CRS CR6 CR7 8 CR9 CR10 CRIl 14 CRIS CRI6 CR17 19 CR20 23 CR24 CR25 26 CR27 28 RI 15 RI6 R17 R18 R19 29 R30 31 R32 39 R40 44 R45 R46 R47 R48 49 R50 52 R53 77 R 78 83 R84 111 R112 R113 125 R126 R 128 132 R 133 R134 135 Ti 2 T3 0160 3892 0160 2479 0160 0013 1901 0033 1884 0254 1884 0058 1901 0660 1901 0314 1901 0461 1901 0033 0811 2244 0698 3614 NOT USED 0811 1918 0811 1857 0
11. Check F3 if blown proceed as follows a Turn front panel CURRENT control fully clockwise maximum b Disconnect anode or cathode of diode CR12 c Turn on power supply no load connected d Tum front panel VOLTAGE controls to see if the 1 000 vdc output can be obtained If it can the probable cause of the low output voltage is one or more of the following 1 CR12 shorted 42 04 shorted 3 OS shorted 4 R26 shorted S R22 shorted e If the 1 000 vde output cannot be ob tained in step d reconnect diode CR12 and turn the front panel VOLTAGE controls to 500 0 vdc f Using the differential voltmeter and os cilloscope check the following b QIA shorted Resistor in voltage control circuit open If not proceed with Step 5 CR15 shorted or other defect in pulse width modulator Use waveforms and normal voltages on schematic to locate 1 Waveform across test points 22 positive lead and 27 waveform shown on schemat ic diagram If waveform is incorrect the Schmitt trigger circuit may be defective Use standard troubleshooting techniques in conjunction with the normal voltages given on the schematic diagram to isolate the defect If no waveform indication is ob served the 20 vdc bias supply CR74 CR7S and C 27 may be defective 2 Voltages across testpoints 52 Da 53 If voltage is not 160 10 vdc CR20 through CRZ3 or C32 may be defective 3 Waveform across test points 60 po
12. The series regulator is controlled by either the voltage or current input circuits Diode gate CR11 CR12 assures that only one input circuit is used at a time 4 4 The voltage input circuit differential ampli fier detects an error voltage that is proportional to the difference between the voltage across its pro gramming resistors and the de output voltage The error signal is passed through the diode gate amplified and applied to the series regulator The amplified error signal causes the series regulator to increase or decrease the output current as required to maintain a constant de output voltage that s equal to the programmed voltage 45 The current input circuit differential ampli fier detects an error voltage that is proportional to the difference between the voltage across its pro gramming resistor R21 and the voltage across cur rent monitoring resistor R20 The voltage across the current monitoring resistor is proportional to the load current The series regulator responds to the amplified error voltage by increasing or decreasing the output current as required to maintain a con stant load current 4 6 The current through the programming resis tors must be held constant The feedback loop of each input circuit strives to maintain a zero differ ence voltage at the input to its differential ampli fier Therefore the programming current is equal to the applied reference circuit voltage divided by the resistance of
13. Tum front panel CURRENT control fully clockwise maximum c Tum front panel VOLTAGE controls until the differential voltmeter indicates maximum rated output voltage d Allow a half hour warm up and then record the differential voltmeter indication e After eight hours differential voltmeter indication should change by less than 3 6 mvdc from indication recorded in step d Connect supply as given in Paragraph Proceed as follows 5 17 Output impedance a Connect test setup shown in Figure 5 3 b Turn front panel CURRENT control fully clockwise maximum Proceed as follows c Adjust front panel VOLTAGE controls until front panel voltmeter indicates 200 0 vde d Adjust the audio oscillator for a 10 vrms Ein S Hz cps output e Calculate and record the output imped ance using the following formula ER Ein R 1 000 ohms Eg measured across power supply front terminals using the AC voltmeter Ein meas ured across audio oscillator output terminals using the AC voltmeter f Using the formula given in step e cal culate and record the output impedance for audio oscillator freguencies of 100 Hz cps 1000 Hz and 600 kHz at 10 vrms g The output impedances calculated and Zout since Zout lt lt R recorded in steps e and f should fall into the fol 5 4 lowing ranges 1 DE to 100 Hz less than 0 01 ohn 2 100 Hz to 1 kHz less than 0 02 ohm 3 1 kHz to 100 kHz less than 0 5 ohm
14. an oscilloscope ground the case at the same ground point as the grounded terminal of the power supply Make certain that the case is not also grounded by some other means power cord O 100K Accuracy 0 1 la 100 1 up to 4KV 0 014 Accuracy Test Equipment Continued Required Type Characteristics Recommended Model Measure impedance Measure impedance Constant current load regulation Measure temperature stability Measure programming coefficients me m ce me aa Measure ripple and noise Load regulation Line regulation Keithiev Instru ments Inc Model 6601A Connect both oscilloscope input leads to the power supply ground and check that the oscilloscope is not exhibiting a ripple or transient due to ground loops pick up or other means 5 6 PERFORMANCE TEST 5 7 The performance check is made using a 115 volt 60 Hz cps single phase input power source The performance check is normally made at a con stant ambient room temperature The temperature range specification can be verified by doing the performance check except temperature stability check at a controlled temperature of 0 C and at a controlled temperature of 55 C If the correct re sult is not obtained for a particular check do not adjust any controls proceed to troubleshooting 5 8 CONSTANT VOLTAGE TESTS 5 9 Rated Output Meter and Output Controls Accuracy Proceed as f
15. eyelets 1 Clip lead as shown below 2 Bend protruding leads upward Bend lead of new APPLY component SOLDER around pro truding lead Apply solder using a pair of long nose pliers as a heat sink OZTTITA BGOZDZAAGAORNNZEORNGA PRIOR r PRWZRDRZDZDUNOREDARZUE ANNA This procedure is used in the field only as an alternate means of repair the factory It is not used within Figure 5 5 Servicing Printed Circuit Wiring Boards Table 5 5 Selected Semiconductor Characteristics Designator Matched differential amplifier 1854 0221 2N4045 Union Carbide 1854 0027 2N2714 G E Q Q7 010 Q12 013 NPN Si planar 70 hpp ic 2 ma Vor 1V 1854 0225 233055 NPN power hpp 35 min at lo 4A VGE 4V 1854 0244 2N2195 G E NPN Si hpg 60 fmin at Ip 1 ma VCE LV Q14 Q16 CR9 CR25 CR26 1901 0461 1N4828 CR61 CR66 CR80 Si rectifier 200 ma 10 prv Table 5 6 Checks and Adjustments After Replacement of Semiconductor Devices 01 02 03 04 Q5 Q6 07 Error amplifier 010 OLL Q17 012 013 Constant voltage differential amplifier Constant voltage load regulation Constant current differential amplifier Constant current load regulation Constant voltage constant current load regulation Series regulator Constant voltage constant current
16. instrument and the instrument described by this manual s 1 13 ORDERING ADDITIONAL MANUALS 1 14 One manual is shipped with each power sup ply Additional manuals may be purchased from your local Hewlett Packard field office see list at rear of this manual for addresses Specify the model number serial number prefix and HP Part Number provided on the title page l 15 OPTIONS OPTION NO DESCRIPTION J13 Permits operation on 23 0Vac 48 63Hz through use of an external accessory 230V to 115V step down transformer l 16 Options are factory modifications of a standard instrument that are requested by the customer 910 Extra Manual Table l 1 Specifications INPUT 115 Vac 10 48 440 Hz 4A 270W STABILITY Under constant ambient conditions total drift for 8 hours following 60 minutes warm up OUTPUT Constant Voltage 0 036 plus 3 mV 0 4000 Vdc 0 50 mA Constant Current 0 25 plus 0 12 mA LOAD REGULATION Constant Voltage Less than 0 005 or 20mV whichever is greater for a full load to no load change in output current Constant Current Less than 2 or 1mA whichever is greater for a full load to no load change in output voltage LINE REGULATION For a change in line voltage of 115Vac 10 at any output voltage and current within rating CONTROLS Voltage controls consist of a three decade thumbwheel switch plus a thumbwheel vernier with 0 002 resol
17. instrument covers 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 voitage 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 periv grounded receptacie to minimize electric shock hazard Operation at line voltages or frequencies in excess of those stated on the data plate 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 necessarv for the user to refer to the instruction manual refer to Table of Contents gt Indicates hazardous voltages GH M l Indicate earth ground terminal 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
18. is clamped to test point 53 and the negative side right side falls a corresponding amount to reverse bias CRIS With CRIS cutoff and CR16 on the current back into TI through TI flows through C19 charging it in oppo site direction and CR16 When C19 is charged to approximatelv 160 volts equal to line voltage storage capacitor the polaritv across TI reverses and maintains the current flow into C19 The voltage across T1 now builds up in the reverse direction and is coupled to the second primary winding which is phase reversed from the first winding When the voltage across the second primary winding reaches approximately 160 volts CR19 is forward biased and the voltage across TI is clamped to the line voltage capacitor 160 volts because the voltage across Ti can no longer in crease the current through the first primary winding of Ti falls to zero and CR16 is cut off At this point C19 has been charged to 320 volts right side is positive CR17 prevents C19 from discharging The current through the second pri mary winding of T1 falls toward zero as the energy stored in the leakage inductance and core of the transformer is retumed to the line voltage storage capacitor The 320 volts across C19 remains until the next puise from the Schmitt trigger causes the action to repeat Thus at the time of the first pulse C19 was charged to 160 volts thereafter the initial condition for C19 is 320 volts It should be noted that if the
19. of QIA and QIB are connected directly to the bases of QZ and Q3 respectively Transistors Q2 and Q3 comprise a differential amplifier that provides required voltage gain The negative feedback from the col lector of Q3 via C6 and R7 to the base of QIA extends the combined frequency response of both differential amplifiers to well beyond 100 kHz xc and reduces the high frequency gain in order to 4 3 prevent power supply oscillation The collector output of Q3 is coupled to the diode gate CR11 4 22 At high frequencies capacitors C3 CA and C5 bypass the base of Q1B the emitters of Q2 and Q3 and the collector of Q1B base of Q2 respectively Thus OlA operates as an emitter follower that drives QIB common base and Q3 is a common emitter driven by Q1B Q2 is effectively bypassed from the circuit This bypassing at high frequencies compensates for the Miller effect capacitances and thus ma ntains high frequency gain approximately equal to the low frequency gain 4 23 Diodes CR3 and CR4 protect OlA from exces sive voltage in either direction by clamping the base to approximately 0 8 volts Resistor R3 protects the programming resistors VOLTAGE thumbwheel con trols from surge currents that result when the voltage controls are programmed up or down rapidly The surge current is caused by the voltage difference between the output voltage and the newly programmed voltage and flows through either CR3 or CR4 depending on whet
20. output currents from each individual supp y Since the inputs to the supplies error amplifiers are not available the two supplies must be connected in straight parallel with one supply operating as a constant current CC source To protect the supplies input voltage amplifiers diodes CRI and CR2 are added between the output terminals and the load as shown in Figure 3 2 If the diodes are not added damage may occur when one supply is turned off with the voltage controls set for zero volts or to some low value To operate the two supplies in parallel proceed as follows a With both supplies turned off connect the load and the protection diodes as shown in Figure 3 2 b Turn on the CC supply leaving the CV supply off set the CC supply s voltage controls for maximum and adjust its current control for one half the desired output current c Turn on the CV supply and with its current control set to maximum adjust the CV supply s voltage controls for the desired output voltage NOTE The CV supply s output voltage will be slightly higher than the voltage across the load by an amount equal to the drop across diode CRI plus the drop in the load connecting wires CV SOURCE CC SOURCE Figure 3 2 Paralleling Two Supplies 3 14 OPERATING CONSIDERATIONS 3 15 PULSE LOADING 3 16 The power supply will automatically cross over from constant voltage to constant current opera tion or the reverse in response to an incre
21. used as a constant voltage source or the voltage control may be used to set the maximum output voltage voltage ceiling when the power supply is used as a constant current source Detailed speci fications are given in Table 1 1 1 3 OVERLOAD PROTECTION 1 4 A crossover feature protects both power sup ply and load in constant voltage operation Auto matic crossover circuitry switches the power supply from constant voltage to constant current operation if the output current exceeds a preset limit This crossover circuitry also protects the load from over voltage during constant current operation by auto matically switching the power supply into constant voltage operation if the output voltage exceeds the preset limit The user can adjust the crossover point via the front panel controls Paragraph 3 1 1 5 The power supply is protected from reverse voltage positive voltage applied to negative termi nal by an internal protection diode and the diode bridge network that shunts current across the output terminals when this condition exists clamping the reverse voltage Protection from reverse current current forced into the power supply in the direction opposite to the output current must be provided by preloading the power supply Paragraph 3 29 The power supply cannot accept reverse current without damage 1 6 COOLING 1 7 Convection cooling is used Nofanis required The power supply has no moving parts except for meter moveme
22. 0225 Power NPN Si 28480 Ri 0686 3955 1 fxd comp 3 9MQ 5 vw 01121 EB 3955 R2 0686 1035 3 fxd comp 10kQ0 5 Vw 01121 EB 1035 R3 0811 1866 2 fxd ww IOKO 1 5w 30ppm 28480 R4 0812 0010 4 fxd ww 3kQ 5 3w 20ppm 28480 R5 0686 0000 i Selected 4w 28480 R6 0811 1866 fxd ww 10k10 Yo SW 30ppm 28480 R7 0686 2435 2 fxd comp 24kQ 5 Yw 01121 EB 2435 R8 9 0757 0480 2 fxd film 432k Q 42190 1 8w 19701 MFSCT 0 R10 0757 0473 1 fxd film 221k2 1 1 8w 19701 MFSCT 0 Ril 0686 2235 2 fxd comp 22kQ 5 Vw 01121 EB 2235 R12 0686 1535 2 fxd comp 15kQ 5 vw 01121 EB 1535 R13 0686 2435 fxd comp 24k2 5 Vw 01121 EB 2435 R14 0757 0452 1 fxd film 27 4kQ 1 1 8w 19701 MFSCT 0 RIS 0811 1204 1 fxd ww 2000 5 Sw 28480 R16 17 NOT USED R18 NOT ASSIGNED R19 0686 2015 1 fxd comp 2000 5 w 01121 EB 2015 R20 0686 1805 1 fxd comp 180 5 Vw 01121 EB 3905 R21 NOT USED R22 0686 6825 1 fxd comp 6 8kQ 5 jaw 01121 EB 6825 R23 0686 3325 4 fxd comp 3 3kQ 5 aw 01121 EB 3325 R24 0686 2445 1 fxd comp 240kQ 5 w 01121 EB 2445 R25 0686 3625 2 fxd comp 3 6kQ 5 aw 01121 EB 3625 R26 0686 6225 1 fxd comp 6 2kQ 5 rw 01121 EB 6225 RZE 0686 4725 2 fxd comp 4 7k 5 Vw 01121 EB 4725 R28 29 NOT USED R30 31 NOT ASSIGNED R32 0686 1035 fxd comp 10kQ 5 aw 01121 EB 1035 R33 0686 1645 1 fxd comp 160k2 5 aw 01121 EB 1645 R34 0686 5135 1 fxd comp 51k2 5 aw 0112 EB 5135 R35 0686 1525 2 fxd comp 1 5kQ 5 jaw 01121 EB 1525
23. 0prv NOT ASSIGNED rect Si 200 mA 180prv NOT USED NOT ASSIGNED NOT USED NOT ASSIGNED NOT USED NOT ASSIGNED rect Si 200 mA 180 prv rect Si 200 mA 10prv rect Si 200 mA 180prv 56289 56289 04062 56289 56289 28480 56289 56289 28480 56289 56289 56289 56289 56289 56289 56289 56289 56289 56289 03508 93332 93332 28480 93332 93332 28480 93332 MFR PART NO 192P2249R8 192P 10492 RCMISE 511 192P 10492 192P10392 192P10392 D39532 30D206G050DC4 30D107G025DH4 30D206G015BB4 192P33392 30D206G105BB4 192P10492 192P2249R8 29C9B5 912P33392 30D756G015CC2 Ai4B IN485B IN485B IN485B IN485B IN485B HP MFR PART NO TQ DESCRIPTION CODE MFR PART NO CR68 1901 0050 1 Diode Si switch 28480 CR69 NOT ASSIGNED CR70 71 1901 0327 rect Si 500 mA 200prv 03508 114B CR72 NOT USED CR73 1901 0033 rect Si 100 mA 180prv 93332 IN485B CR74 78 1901 0327 rect Si 500 mA 200prv 03508 114B CR79 1901 0033 rect Si 200 mA 180prv 93332 IN485B CR80 1901 0461 rect Si 200 mA 180prv 93332 IN485B CR8i 82 1901 0033 rect Si 200 mA 180prv 93332 IN485B Qi 1854 0221 k 7 SS NPN diff amp si 28480 Q2 7 10 1854 0027 9 SS NPN Si 03508 2N2714 Q8 1853 0099 1 SS PNP Si 28480 Q9 NOT ASSIGNED Q11 1954 0225 2 Power NPN Si 28480 Q12 13 1854 0027 SS NPN Si 03508 2N2714 Q14 1854 0244 2 SS NPN Si 03508 2N2195 Q15 1853 0041 1 SS PNP Si 02735 40362 016 1854 0244 SS NPN Si 28480 017 1854
24. 13 to the base of Q7 For low frequencies coupling is via R38 for high frequencies coupling is via C13 Thus the impedance seen looking to the right of the base of Q7 remains low at high frequencies to reduce the Miller effect capacitance of Q7 Resistor R36 forms a voltage divider with R38 across VRI to provide proper base bias for Q7 For stabilitv negative feedback is provided from the collector of Q7 via C12 and R34 to the base of O6 The collector output of Q7 is coupled to the series regulator driver base of Q10 via R37 4 32 SERIES REGULATOR 4 33 The series regulator Q11 controls the out put current in response to the voltage and current error signals Transistor Q10 is the driver for Oli In constant voltage operation the output voltage is adjusted so that it remains constant for changing loads In constant current operation the output current is maintained constant for changing loads and the output voltage is allowed to vary Capacitor C16 eliminates the Miller effect capacitance of 010 Transistor 017 is a current bleed for the series regulator and serves to rapidly discharge output capacitor C28 The voltage across Q11 is monitored by the Schmitt trigger 4 34 SCHMITT TRIGGER 4 35 The Schmitt trigger Q15 Q16 pulses the pulse width modulator via pulse transformer T3 when the voltage collector to emitter across series regulator Q11 falls below a predetermined level When the voltage across Q11 rises above ano
25. 3 7 Constant Current To select a constant cur rent output proceed as follows a With supply off short output terminals then turn on supply set CURRENT control for desired output current b Open output terminals and set VOLTAGE thumbwheel controls for maximum output voltage allowable voltage limit as determined by load conditions Ifa load change causes the voltage limit to be exceeded the power supply will auto matically crossover to constant voltage output at the preset voltage limit and the output voltage wili drop proportionately in setting the voltage limit allow ance must be made for high peak voltages which can cause unwanted crossover Refer to Paragraph 3 17 CAUTION High output current surges are possible even though supply is in constant cur rent operation because of charge on output capacitors 3 8 CONNECTING LOAD 3 9 Output terminals are provided at the rear of the power supply The terminals are marked and The positive or negative output terminal may be grounded by shorting the center pin and case of the applicable UG 931 U plug or by grounding the wire from the plug to the chassis or neither grounded floating operation permitted to 2 000 Vdc off ground WARNING To avoid injurv to personnel due toarc ing turn off the power supply before connecting or disconnecting the load connectors 3 19 Each load should be connected to the power supply output terminals using separate pairs of c
26. 30 TROUBLE ANALYSIS 5 31 Before attempting trouble analysis a good understanding of the principles of operation should be acquired by reading Section IV of this manual Once the principles of operation are understood logical application of this knowledge in conjunc tion with significant waveforms and normal voltage information should suffice to isolate a fault to a part or small group of parts Normal voltages and tolerances are provided on the overall schematic diagram at the rear of the manual The voltages are positioned adjacent to test points numbered balloons printed on the schematic diagrams and printed wiring boards In addition waveform photographs taken at significant test points are provided on the apron of the schematic diagram 5 32 In most cases a fault will manifest itself as either excessive voltage output or low voltage out put less than 40 volts The latter is by far more common since the pulse width modulator requires a series of trigger pulses at the proper intervals and sequence and the skipping of a pulse or an excessivelv long on interval will cause the transformer TI to saturate and blow fuse F3 Thus the pulse width modulator ceases to function causing no high voltage to appear at the output NOTE Under no circumstances should fuse F3 be replaced with aregular or slo blo fuse 5 33 With the exception of a component failure in the Line Voltage Bridge Storage Capacitor circuit the Pulse width Modul
27. 698 3614 0686 5615 0811 1867 0811 1857 0698 3614 9100 1890 DESIG PART NO TQ LD UI wma pu werak DESCRIPTION Pulse Width Modulator Board MFR CODE MFR PART NO NOT USED NOT ASSIGNED NOT USED NOT ASSIGNED NOT USED NOT ASSIGNED NOT USED NOT ASSIGNED NOT USED fxd paper 0 022uf 400 Vdc 28480 fxd paper 0 047uf 400 Vdc 56289 NOT ASSIGNED NOT USED NOT ASSIGNED NOT USED i fxd paper 0 14f 400 Vdc 56289 NOT USED NOT ASSIGNED NOT USED 191P4730454 160P 10494 NOT ASSIGNED NOT USED NOT ASSIGNED rect Si 200 mA 180prv 93332 IN485B Thyristor 28480 i Thyristor 28480 rect Si 22A 900prv 28480 Select for 860 min piv 02735 NOT ASSIGNED rect Si 200 mA 100prv 28480 rect Si 200 mA 180prv 93332 IN485B NOT USED fxd ww 390 5 2w 75042 fxd film 430 5 2w 27167 IN1206A BWH2 39R J FP42 2 T00 43RO J NOT USED NOT ASSIGNED NOT ASSIGNED NOT ASSIGNED fxd ww 30kQ 5 5w 63743 1 10XM fxd ww 4000 5 Sw 28480 fxd film 430 5 2w 27167 fxd comp 5600 5 vw 01121 NOT ASSIGNED NOT USED NOT ASSIGNED NOT USED NOT ASSIGNED NOT USED fxd ww 15kQ 5 5w 63743 5XM NOT ASSIGNED fxd ww 4000 5 Sw 28480 fxd film 430 5 2w 27167 NOT USED Pulse Transformer 28480 FP42 2 TOO 43RO J EB 5615 FP42 2 TOO 43RO J REF DESIG HP PART NO 1901 0330 0689 1855 0811 1815 0180 1845 1901 0330 0811 1918 0686 1015 TQ DESCRIPTION MFR PART NO Hi
28. Div Danbury Conn E F Johnson Co Waseca Minn IRC Div of TRW Inc Philadelphia Pa Howard B Jones Div of Cinch M g Corp New York N Y Kurz and Kasch Inc Dayton Ohio Kilka Electric Corp Mt Vernon N Y Littlefuse Inc Des Plaines 1ll Minnesota Mining and M g Co St Paul Minn Minor Rubber Co inc Bloomfield N J James Millen Mfg Co Inc Malden Mass J W Miner Co Compton Calif Use Code 71785 assigned to Cinch Mfg Co Chicago Ill 6 3 Table 6 3 Code List of Manufacturers Continued CODE TA CODE No MANUFACTURER ADDRESS No MANUFACTURER ADDRESS 76530 Cinch City of Industry Calif 835081 Grant Pulley and Hardware Co 768541 Oak Mig Co Div of Oak West Nyack N Y Electro Netics Corp Crystal Lake IL 835941 Burroughs Corp Electronic 770681 Bendix Corp Electrodynamics Div Components Div Plainfield N J No Hollywood Calif 838351 U S Radium Corp Morristown N J 771221 Palnut Co Mountainside N J 4 838771 Yardeny Laboratories Inc 77147 Patton MacGuyer Co Providence R L New York N Y 77221 Phaostron Instrument and Electronic Co 841711 Arco Electronics Inc Great Neck N Y South Pasadena Calif 844111 TRW Capacitor Div Ogallala Neb 772521 Philadelphia Steel and Wire Corp 866841 RCA Corp Electronic Components Philadelphia Pa Harrison N J 773421 American Machine and Foundrv Co 86836 Rummel Fibre Co Newark N I Potter and Bru
29. Howard Industries Div of Msl Ind Inc Freeport Ill Racine Wisc 92825 Whitso Inc Schiller Pk Ill 810731 Grayhill Inc La Grange Ill 93332 Svivania Electric Prod Inc Semi 814834 International Rectifier Corp conductor Prod Div Woburn Mass El Segundo Calif 93410 Essex Wire Corp Stemco 817511 Columbus Electronics Corp Yonkers N Y Controls Div Mansfieid Chio 820991 Goodyear Sundries Mechanical Co Inc 941441 Raytheon Co Components Div New York N Y Ind Components Oper Quincy Mass 82142 A rco Speer Electronic Components 941541 Wagner Electric Corp Du Bois Pa Tung Soi Div Livingston N J 822191 Svivania Electric Products Inc 942221 Southco Inc Lester Pa Electronic Tube Div Receiving 95263 Leecraft Mfg Co Inc L I C N Y Tube Operations Emporium Pa 953341 Methode Mfg Co Rolling Meadows Ill 823891 Switchcraft Inc Chicago Ill 957121 Bendix Corp Microwave 82647 Metals and Controls Inc Control Devices Div Franklin Ind Products Group Attleboro Mass 95987 Weckesser Co Inc Chicago Ill 82866 Research Products Corp Madison Wis 967911 Amphenol Corp Amphenol 828771 Rotron Inc Woodstock N Y Controls Div Janesville Wis 82893 Vector Electronic Co Glendale Calif 974641 Industrial Retaining Ring Co 83058 Carr Fastener Co Cambridge Mass Irvington N J 831861 Victorv Engineering Corp 97702 IMC Magnetics Corp Eastern Div Springfield N J Westbury N Y 83298 Be
30. R123 and C30 charges rapidly Diode CR81 clamps the base of series regulator driver Q10 until C31 is charged This prevents the series regulator from delivering current to the output before the power supply cir cuits have stabilized Diode CR80 and R124 clamp the voltage across C 31 to approximately 15 volts otherwise C31 would charge to approximately 40 volts Q8 CR73 prevent F3 from blowing at turn on off 4 50 When the power supply is turned off C30 discharges rapidly through RI21 and R122 and C31 discharges rapidly through CR79 Diode CR82 clamps the base of Q10 immediately after an inter ruption of the line voltage to shut down the series regulator and thus preventing anv possibilitv of the circuit going into an unstabie state before the bias supplies discharge 4 51 REFERENCE CIRCUIT 4 52 The reference circuit provides 12 4 Vdc operating voltage for the error amplifier and voltage and current differential amplifiers and 6 2 and 9 4 Vdc reference voltages for the voltage and cur rent programming currents The reference circuit is powered by C29 charged to approximately 40 Vdc via full wave rectifier CR76 CR77 4 55 4 53 Differential amplifier Q12 Q13 detects the voltage difference error between the 46 2 volts zener diode VR2 at the base of Q13 and the voltage at the center of voltage divider R88 R89 12 4 volts volts across divider resistors are equal The amplified error across the collectors of Q12 and
31. R22 current input or by R4 R5 in parallel plus R6 in series voltage input Capaci tor C29 is the storage capacitor that powers the reference circuit Diode CR78 prevents C 29 from discharging back into the turn on turn off circuit 4 7 When the voltage across the series regulator falls below a predetermined level the Schmitt trigger pulses via pulse transformer T3 the pulse width modulator which produces an approximately rectangular voltage pulse The width of the pulse produced by the pulse width modulator is primarily determined by the dc output voltage level and to a lesser extent by the line voltage amplitude High line voltage corresponds to a narrower pulse width high output voltage to a wider pulse width The pulse from the pulse width modulator is stepped up in voltage by high voltage transformer Ti rectified by the high voltage bridge and provides a charging current to the high voltage storage capacitor 4 8 The voltage across the series regulator rises exactly as the voitage rises across the high voltage storage capacitor When the voltage across the series regulator rises above a predetermined level the Schmitt trigger sends another pulse to the pulse width modulator to end the pulse output of the pulse width modulator Thus the charging of the high voltage storage capa itor ceases 4 9 To summarize the series regulator main tains the output voltage or current constant in response to error signals from the voltag
32. Switch See Figure 5 1 Power supply load Model 6521A 5 000n 5 200 W 6522A 20 000n 45 200 W 6525A 80 000n 5 200 W Resistive Loads 1 20 W 20ppm temp coeff Current Measure current Sampling 4 terminals calibrate meter Resistor Model Value 6521A 104 6522A 204 6525A 404 Measure impedance IKA 1 2 W non inductive Si Table 5 1 2 000 ohms 5 20 W Audio Oscillator SHz 600KHz Accuracy 2 Output 10vrms Shorting Switch Controlied Temperature Oven Resistance Box Make before break contacts Capacitor Olufd 4000 wvde Voltage Divider 5 3 MEASUREMENT TECHNIQUES 5 4 All measurements given in this manual are with a negative power supply output positive termi nal grounded to chassis When measuring perform ance of the power supply it is important that the connection to the output terminal does not introduce additional resistance For voltage measurements use a T connector at the positive output terminal and connect the load to one output of the T connec tor and the measuring device to the other output of the T connector For current measurements con nect a four terminal current monitoring resistor in series with the load resistor and connect both to one output of the T connector Connect the meas uring device across the current monitoring resistor 5 5 When using
33. arts in alpha O U numeric order by reference designators and provides the following information a Reference Designators Refer to Table 6 1 b Description Refer to Table 6 2 for ab breviations c Total Quantity TQ Given only the first time the part number is listed except in instruments containing many sub modular assemblies 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 Num ber Refer to Table 6 3 for manufacturer s name and address f Hewlett Packard Part Number g Recommended Spare Parts Quantity RS for complete maintenance of one instrument during one year of isolated service h Parts not identified by a reference desig nator are listed at the end of Table 6 4 under Me chanical and or Miscellaneous The former consists of parts belonging to and grouped by individual as semblies the latter consists of all parts not im mediately associated with an assembly 6 3 ORDERING INFORMATION 6 4 To order a replacement part address order or inquiry to your local Hewlett Packard sales office ses lists at rear of this manual for addresses Specify the following information for each part Model complete serial number and any Option or special modification 7 numbers of the instrument Hewlett Packard part number circuit reference des ignator and description To order a part not listed
34. ase over the preset limit in the output current or voltage respectively Although the preset limit may be set higher than the average output current or voltage high peak currents or voltages as occur in pulse loading may exceed the preset limit and cause crossover to occur To avoid this unwanted cross over the preset limit must be set for the peak requirement and not the average 3 17 OUTPUT IMPEDANCE 3 18 In constant current operation the voltage programming resistance VOLTAGE thumbwheel con trols effectively shunt the output terminals Thus the output impedance at dc is approximatelv equal to the voltage programming coefficient 2 000 ohms per volt times the voltage setting Thus fora 500 Vdc setting the output impedance is approxi mately 1 megohm As the frequency increases the output capacitance of the power supply lowers the output impedance In constant voltage operation the output impedance is low see specifications Table 1 1 3 19 OUTPUT CAPACITANCE 3 20 A capacitor internal across the output terminals of the power supply helps to si oply high current pulses of short duration during con stant voltage operation Any capacitance added externally will improve the pulse current capability but will decrease the safety provided by the con stant current circuit A high current pulse may damage load components before the average output current is large enough to cause the constant cur rent circuit to oper
35. ate 3 21 The effects of the output capacitor during constant current operation are as follows 3 3 a The output impedance of the power sup ply decreases with increasing frequency b The rise time of the output voltage may be increased c A large surge current causing a high power dissipation in the load occurs when the load impedance is reduced rapidiy 3 22 TURN ON AND TURN OFF 3 23 There is no overshoot at turn on or turn off of the power supply However it is recommended that the load be capable of withstanding a maximum charge rate of 3 000 volts per second and a maxi mum discharge rate of 10 000 volts per second 3 24 NEGATIVE VOLTAGE LOADING 3 25 If a negative voltage reverse voltage is applied to the output terminals positive voltage applied to negative terminal the internal protection diode and the diode network will conduct shunting current across the output terminals and limiting the voltage to the forward voltage drop of the diodes approximately 5 volts 3 26 NEGATIVE CURRENT LOADING 3 27 Certain types of loads may cause current to flow into the power supply in the direction opposite to the output current This reverse current cannot be tolerated by the power supply and therefore pre loading will be necessary Forexample if the load delivers 50 milliamperes to the power supply with the power supply output voltage at 500 Vdc a resistor equal to 10 000 ohms 500 50 x 1073 should be connected acros
36. ator the High voltage Transformer or the High voltage Bridge Storage Capacitor circuit all failures can be isolated to the Piggy back power supply system This allows a great deal of trouble shooting to be done with the pulse width modulator inoperative so that the maxi mum voltage on the unit is the Piggy back power supply which does not exceed 40 volts 5 34 In addition to the normal voltages and wave forms procedures are included for isolating com mon troubles as follows GA a Procedure for checking the reference cir cuit Troubie in this circuit chould show up in manv wavs because it supplies internal operating voltages for the power suppiv b Procedures for checking the voltage feed back loop for the two most common troubles high or low output voltage Table S 2 and 5 3 respec tivelv NOTE Check the input power source for low or high voltage before assuming that the power sup ply is at fault The turn on tum off circuit will cause output to have excessive ripple and poor regulation if the line voltage is low c Table 5 4 which gives the probable causes for some common troubles 5 35 REFERENCE CIRCUIT Turn the front panel VOLTAGE and CURRENT controls fully clockwise maximum Ground OUTPUT to chassis Turn on power supply no load connected and proceed as follows a Using the differential voltmeter check the 40 vdc between test points 16 and 37 If the voltage indication is not 40 2 v
37. c HEWLETT PACKARD HIGH VOLTAGE DC POWER SUPPLY MODEL 6525A OPERATING AND SERVICE MANUAL FOR SERIALS 2113A 2682 AND ABOVE For Seriais Above 2113A 2682 a Change Sheet May Be Included Manual Part No 06525 90003 PRINTED July 1981 Microfiche Part No 06525 90004 MANUAL CHANGES Model 6525A PAGE 2 CHANGE 2 In Section I page 1 1 paragraph 1 9 and wherever mentioned in the manual change the maximum float voltage specfication of the power supply from 2KVdc to 4KVde In the replaceable parts list page 6 10 add under Chassis Mount ed Parts Isolation Transformer HP P N 06525 60006 qtv 1 6 20 84 o HEWLETT PACKARD HIGH VOLTAGE DC POWER SUPPLV MODEL 6525A OPERATING AND SERVICE MANUAL FOR SERIALS 2113A 2682 AND ABOVE For Seriais Above 2113A 2682 a Change Sheet Mav Be Included Manual Part No 06525 90003 PRINTED July 1981 Microfiche Part No 06525 90004 SAFETV SUMMARV The following general safetv 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 safetv standards of design manufacture and intended use of the instrument Hewlett Packard Companv 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
38. d to the line voltage bridge and storage capacitor Each side of the line input has an eight ampere fuse for protection A pilot lamp is connected across the primary of T2 Each of the three secondary windings of T2 is center tapped for full wave rectification 4 15 20 VDC BIAS SUPPLY 4 16 The 20 Vdc bias supply consists of diodes CR74 and CR75 which provide full wave rectifica tion and capacitor C27 which provides filtering The 20 Vdc is used by both the Schmitt trigger and the series regulator 4 17 40 VDC BIAS SUPPLY 4 18 The 40 Vdc bias supply consists of diodes CR70 and CR71 which provide full wave rectifica tion and capacitor C26 which provides filtering The 40 Vdc is used by the series regulator 4 19 VOLTAGE INPUT 4 20 The voltage input circuit is basically a dif ferential amplifier QIA QIB that detects any voltage difference between the programmed output voltage and the actual output voltage The differ ential amplifier output voltage varies in proportion to the power supply output voltage variation Transistors QIA and QIB are a matched pairina single package to ensure that both are at the same temperature and thus improve stabilitv 4 21 There are two inputs to the base of QIA one determined bv the programmed voltage VOLTAGE thumbwheel controls S201 202 and 203 and the other by the collector voltage of Q3 negative feed back The base input of Q1B is determined by the positive output voltage The collectors
39. dc diode CR70 OR71 or capacitor C26 is defective b Using the differential voltmeter check the 12 4 vdc between test points 18 and out the voltage indication is not 12 4 1 0 vdc transistor Q12 Q13 or Q14 is probably defective c Using the differential voltmeter check the 6 2 vdc between test points 17 and out If the voltage indication is not 6 2 0 30 vdc diode VR2 is probably defective d Using the differential voltmeter check the 9 4 vdc between test points 32 and out If the voltage indication is not 9 4 0 40 vdc diode VR4 is probably defective e Using the differential voltmeter check the 20 vdc between test points 28 and 27 If the indication is not 19 i vdc CR74 CR75 or C27 is probably defective If 5 36 HIGH OUTPUT VOLTAGE Proceed as follows a Turn front panel CURRENT control fully clockwise maximum b Turn on power supply no load connected c Turn front panel VOLTAGE controls to 500 0 vdc d Using the differential voltmeter proceed as instructed in Table 5 2 Table 5 2 High Output Voltage Trouble shooting Response 0 1 vde 18 to 20 vdc 6 vdc 1 to 1 1 vdc Probable Cause 010 or Oll shorted Proceed to Step 2 CRI or R32 open Proceed to Step 3 More positive than 6 8 vde a QIA or 03 shorted 6 2 to 6 8 vde b QIB Q2 or R13 open Proceed with Step 4 More positive than 0 vdc a RS shorted 0 vdc 5437 LOW OUTPUT VOLTAGE
40. e sides and rear of the power supply to permit free flow of cooling air The power supply should be located in an area where the ambient temperature does not exceed 55 C el 10 48 to 440Hz power source The power supply is shipped for operation at 115 volts nominal At 115 volts 60Hz the full load requirement is 270 watts at 4 0 amperes See page l l for option J13 which provides for operation from 230Vac 2 13 POWER CABLE 2 14 To protect operating personnel the National Electrical Manufacturers Association NEMA recommends that the instrument panel and cabinet be grounded This instrument is equipped with a three conductor power cable The third conductor is the ground conductor and when the cable is plugged into an appropriate receptacle the instru ment is grounded The offset pin on the power cable three prong connector is the ground connection 2 15 To preserve the protection feature when operating the instrument from a two contact outlet use a three prong to two prong adaptor and connect the green lead on the adaptor to ground 2 16 This unit is factory eguipped with a power cord plug that is most appropriate for the user s location If a different power cord is desired contact your nearest HP sales ofiice 2 17 REPACKAGING FOR SHIPMENT 2 18 To insure safe shipment of the instrument itis recommended that the package designed for the instrument be used The original packaging material is reusable If i
41. e or current input circuits However the voltage across the series regulator is kept within predetermined limits bv the action of the Schmitt trigger and pulse width modulator 4 10 If the output of the power supply is shorted internal protection diode CR72 becomes forward biased and the charge on the high voltage storage capacitor is conducted to the output via CR72 R120 limits surges This protects the series regulator which otherwise would have to take almost the full output voltage that existed at the time the power supply was shorted The 40 Vdc bias supply assures that CR72 is reverse biased during normal operation and also provides opera ting bias for the series regulator It should be noted that the 40 Vdc bias supplv and the series regulator with its control and reference circuits forms a complete regulated 0 to 40 Vde at 0 to 200 mA power suppiv 4 11 To allow the power supply circuits to stabilize before power is delivered to the output the turn on circuit provides a time delay by clamping the series regulator via CR81 To permit rapid turn off delayed by the various storage capacitors the turn off circuit clamps the series regulator via CR82 to prevent the high voltage storage capacitor from conducting charge to the output 4 12 CIRCUIT DESCRIPTION See overall schematic at back of manual 4 13 AC INPUT 4 14 The 115Vac 10 single phase 48 to 440Hz input is applied to auxilliary power trans former T2 an
42. efore returning the power supply to mended model for performing the instructions given normal operation repeat the performance check to in this section Upon receipt of the power supply ensure that the fault has been properiv corrected the performance check should be made This check and that no other faults exist Before doing any is suitable for incoming inspection Additional maintenance checks turn the power supply on specification checks are given in Paragraphs 5 23 allow a half hour warm up and read the measure through 5 25 If a fault is detected in the power ment techniques discussed in the following para supply while making the performance check or graph during normal operation proceed to the trouble Table 5 1 Test Equipment Required a E Recommended Type Characteristics Use Model AC Voltmeter HP 3476 A B Accuracy 2 Sensitivity imv Measure AC voltages full scale min Variable Range 90 130 volts Equipped Vary and measure AC Voltage with voltmeter accurate within input voltage Transformer i volt 1 KW rating f A HP180C with Oscilloscope Sensitivity 1 mv cm min Measure ripple and 1821A and 1801A transient response plug ins Differential Sensitivitv imv full scale min Measure regulation HP3476A B Voltmeter Calibrate meter Measure transient response Rate 60 400 Hz 2usec rise and fall time 250V 1A Repetative Load
43. er supply is operated from a 115Vac inspected and found free of mechanical and elec trical defects If damage to the shipping carton is evident ask that the carrier s agent be present when the power supply is unpacked As soon as the power supply is unpacked inspect it for any damage that may have occurred in transit Also check the cushioning material for signs of severe stress may be indication of internal damage Save all packing materials until the inspection is completed If damage is found proceed as in structed in the Claim for Damage in Shipment notice on the inside of the back cover of this manual 243 MECHANICAL CHECK 2 4 Check that there are no broken knobs or connectors that the external surface is not scratched or dented that the meter face is not damaged that all controls move freely and that the fuses at rear of power supply are in place and of the correct rating two 8 ampere and one 6 ampere type 3AB Any external damage may be an indication of internal damage 2 5 ELECTRICAL CHECK 2 6 Check the electrical performance of the power supply as soon as possible after receipt A performance check that is suitable for incoming inspection is given in Paragraphs 5 6 through 5 22 2 7 INSTALLATION DATA 2 8 The power supply is shipped ready for bench or standard 19 inch relay rack operation 2 9 LOCATION 2 10 Because the power supply is cooled by convection there must be enough space along th
44. ewound z Watt 94009 04072 04213 04404 04713 05277 03347 05820 06001 06094 06486 06540 06555 06666 06751 06776 06812 07137 Table 6 3 Code List of Manufacturers MANUFACTURER ADDRESS Jamaica N Y New Bedford Mass EBY Sales Co Inc Aerovox Corp Sangamo Electric Co S Carolina Div Allen Bradley Co Litton Industries Inc Beverly Hilis Calif TRW Semiconductors Inc Lawndale Calif Pickens 5 C Miiwaukee Wis Texas Instruments Inc Semiconductor Components Div Dallas Texas Manchester N E Rockford Il Dover Ohio Saugerties N Y Fenwal Laboratories Morton Grove Ili Amphenol Corp Broadview Ill Radio Corp of America Solid State and Receiving Tube Div Somerville N J G E Semiconductor Products Dept Svracuse N X Compton Calif RCL Electronics Inc Amerock Corp Sparta Mfg Co Ferroxcube Corp Eldema Corp Transitron Electronic Corp Wakefield Mass Pvrofilm Resistor Co Inc Cedar Knolls N J Arrow Hart and Hegeman Electric Co Hartford Conn ADC Electronics Inc Harbor City Calif Caddell amp Burns Mig Co Inc Mineola N X kHewlett Packard Co Paio 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 De
45. gh Voltage Bridge Board NOT USED NOT ASSIGNED NOT USED NOT ASSIGNED NOT USED NOT ASSIGNED NOT USED NOT ASSIGNED NOT USED NOT ASSIGNED rect Si 400 mA 800prv NOT USED NOT ASSIGNED NOT USED NOT ASSIGNED NOT USED NOT ASSIGNED NOT USED NOT ASSIGNED fxd comp 1 8MQ 5 lw GB 1855 fxd ww 7 5k Yo 3w 242E7525 Voltage Doubier Board NOT USED NOT ASSIGNED NOT USED NOT ASSIGNED NOT USED NOT ASSIGNED NOT USED NOT ASSIGNED NOT USED NOT ASSIGNED NOT USED NOT USED NOT USED fxd elect luf 450 Vdc Vitg Dbir NOT USED NOT ASSIGNED NOT USED NOT ASSIGNED NOT USED NOT ASSIGNED NOT USED rect Si 400 mA 800prv NOT ASSIGNED fxd ww 130k 25 t w Vltg Dblr fxd comp 1000 5 vw Vitg Dbir 01121 REF DESIG CI C2 6 C7 9 C10 CH C12 13 C14 15 C16 C17 18 C19 20 22 C24 C25 C26 27 29 31 C32 CR1 4 CRS CR6 CR7 8 CR9 CRIO CR11 23 CR24 CR25 28 CR29 CR30 41 CR42 59 CR60 68 CR69 CR70 71 CR72 FI HP PART NO 0160 4763 0160 2570 0160 4119 0180 1893 0160 4117 0180 1840 1901 0327 1450 0566 2110 0036 2110 0056 9100 1892 9100 1893 9100 1891 1120 1347 1120 1346 2100 1884 TQ dd wn pi jaak jot jur jar DESCRIPTION Chassis Mounted Parts paper film glasscase 0 lmf 4kV NOT USED NOT ASSIGNED NOT USED NOT ASSIGNED NOT USED NOT ASSIGNED NOT USED NOT ASSIGNED fxd paper 2 3uf 400 Vdc NOT USED NOT ASSIGNED
46. her the programming is up or down respectively 4 24 Capacitor Ci couples high frequency tran sient and ripple voltages in the negative output to the base of QIA via C2 and R2 The voltage across Cl is large because it is connected between the negative output bus and the base of QIA which is approximately at the positive bus potential Due to rapid down programming or shorting the output of the power supply heavy discharge currents from Cl occur R15 limits the magnitude of these currents and CRI provides a path to the output terminals RI is used to bleed off any D C leakage current of Cl and thus prevent a voltage build up at point 1 C2 prevents the D C leakage current of Ci from reaching the base of QIA thus improving the D C stability of the power supply R2 limits the amount of high frequency coupling to the base of QIA via C2 RIS and Cl CR2 couples C1 to the base of Q A via R15 and R2 to assure a safe rate of voltage rise across the output when the supply is turned on 4 25 CURRENT INPUT 4 26 The current input circuit is basically a dif ferential amplifier Q4 Q5 that detects any current difference between the programmed output current proportional to voltage across CURRENT control R21 and the actual output current proportional to voltage across current monitoring resistor R20 The differ ential amplifier output voltage varies in proportion to the output current variation 4 27 The input to the differential a
47. justment and Calibration Summary Paragraph Reference Control Device Meter Spring Replace VR4 suspension If pointer moves repeat Steps C and d 5 45 VOLTMETER TRACKING 5 46 Proceed as follows a Connect the differential voltmeter and the 100 1 voltage divider to the T connector b Turn front panel VOLTAGE controls until the differential voltmeter indicates maximum rated voltage output of power supply c Adjust R117 until front panel voltmeter indicates 6521A 5522A 6525A Kilovolts DC i 2 4 5 47 AMMETER TRACKING 3 48 Proceed as follows a Connect test setup shown in Figure 5 4 b Turn front panel VOLTAGE controls to maximum c Turn front panel CURRENT control until differential voltmeter indicates 2 0 vdc d Adjust R119 until front panel ammeter in dicates maximum rated output current of the supply 5 49 CONSTANT VOLTAGE PROGRAMMING CURRENT 5 50 Proceed as follows a Using the differential voltmeter check voltage across test points 17 and OUT If voltage is greater than 6 2 vdc R4 should be 3 000 ohms if voltage is less than 6 2 vdc R4 should be 2 600 ohms i b Connect the differential voltmeter and the 100 1 voltage divider to the T connector c Connect the resistance box set to 100 000 ohms in place of RS d Turn front panel VOLTAGE controls to 1 000 vdc e Adjust the resistance box until the differ ential voltmeter indication is 1 000 5 0 vde f Choose R5 equa
48. justment of R7 Paragraph 5 57 Noisy programming resistors CR3 or CR4 leaky R4 R5 R6 or R86 noisy or drifting Ol 02 or 03 defective Check reference circuit Paragraph 5 35 Noisy programming resistor R21 R22 noisy or drifting 04 or OS defective CR9 leakv Check adjustment of R7 Paragraph 5 57 Check C10 Check voltage programming resistors and input circuit Check R23 and R24 Check adjustment of R91 Before replacing a semiconductor device refer to Table 5 5 which lists the characteristics of each device and the suggested commercial replacement After replacing a semiconductor device refer to Table 5 6 for checks and adjustments that may be necessary If a check indicates a trouble refer to Paragraph 5 28 If an adjustment is necessary refer to Paragraph 5 41 Excessive heat or pressure can lift the copper strip from the board Avoid damage bv using a low power soldering iron 50 watts maximum and following these instructions Copper that lifts off the board should be cemented in place with a quick drying acetate base cement having good electrical insulating properties A break in the copper should be repaired by soldering a short length of tinned copper wire across the break Use only high quality rosin core solder when repairing etched circuit boards NEVER USE PASTE FLUX After soldering clean off any excess flux and coat the repaired area with a high quality electrical var
49. l to the resistance value required in step e RS must be greater than 30K if carbon composition 10K if metal film with a temperature coefficient of 100 ppm 5 51 OUTPUT VOLTAGE LINE REGULATION 3 52 Proceed as follows a Connect the differential voltmeter to the T connector b Connect the variable voltage transformer between input power source and power supplv power input c Turn front panel VOLTAGE controls until the differential voltmeter indicates 1 000 vdc d Adjust variable voltage transformer to 104 volts e Adjust R91 so that the voltage indicated by the differential voltmeter does not change more than 50 0 mvdc as the variable voltage transformer is varied from 104 to 107 volts This may be easily achieved by noting value at 104 then setting adjust to return to this value at 127 Repeat several times 5 53 VOLTAGE OUTPUT STABILITY 5 54 Proceed as follows a Connect the oscilloscope to the T con nector b Connect the resistance box set to 24 000 ohms in place of R7 c Turn front panel VOLTAGE OUTPUT con trols to 1 000 vde d Adjust the resistance box until there are no oscillations detected on the oscilloscope e Choose R7 equal to the resistance value required in step d SECTION VI REPLACEABLE PARTS 6 1 INTRODUCTION Table 6 1 Reference Designators Continued plug vacuum tube transistor neon bulb 6 2 This section contains information for ordering replacement parts Table 6 4 lists p
50. line and load regulation Reference circuit amplifier Constant voltage constant current line regulation Reference circuit series regulator Constant voltage constant current line regulation Load regulation Schmitt Trigger bell Table 5 6 Checks and Adjustments After Replacement of Semiconductor Devices Continued Reference mum Gee Ja OR3 OR4 t Protection diodes GR72 CR15 CR16 SCR s CR20 CR23 CR70 CR71 CR74 CR75 CR30 CR41 CR30 CR47 Bridge rectifier Voltage across 024 mmm 6525A ONLY VRI VRS 6 2 vde bias Constant voltage constant current line and load regulation VR2 VR3 Positive reference voltage 6 2 vdc Line and load regulation of 6 2 vde R91 Negative reference voltage 9 4 vda Line and load regulation of 9 4 vde Constant voltage load regulation Constant voltage constant current regulation Bridge rectifier Voltage across C32 Full wave rectifier Voltage across C26 Voltage across C27 Fuil wave rectifier Full wave rectifier Voltage across C30 Bridge rectifier Voltage across C24 5 41 ADJUSTMENTS AND CALIBRATIONS matic diagram If an adjustment or calibration can l not be performed troubleshooting is required 5 42 Adjustments and calibrations may be reguired Table 5 7 summarizes the adjustments and calibra after performance testing tro
51. line voltage were high the rise rate for the voltage across Ti to reach clamping level CR19 forward biased would be faster and therefore the pulse width would be narrower High output voltage however causes the pulse width to be wider because the current in Tl is smaller for high output voltages 4 45 The following networks suppress voltage spikes that occur primarilv because of the SCR switching C20 and R46 L2 and R16 L3 and R17 and C22 Capacitor C21 and R47 suppress ringing in T1 Diodes CR25 and CR26 are clamps to prevent the SCR gates from pulling T3 negative with respect to test point 53 otherwise heavv current would flow through T3 and the applicable SCR gate causing possible disturbances to the circuit 4 46 HIGH VOLTAGE BRIDGE AND STORAGE CAPACITOR 4 47 The high voltage bridge connected across the third winding of TI full wave rectifies the out put of the pulse width modulator after voltage step up by T1 and charges high voltage storage capacitor C24 Diode CR72 provides internal protection if the power supply output is shorted This diode will then conduct charge directly from high voltage storage gt capacitor C24 to the output thus protecting the serie series regulator Resistor R120 limits surges Capaciter C28 is the output capacitor 4 48 TURN ON TURN OFF CIRCUIT 4 49 The input voltage from T2 is full wave rectified by CR76 and CR77 When the power sup ply is turn on C31 charges slowly through
52. lle Pa ROH Supply Co Vernon Calif Airco Speer Electronic Components Bradford Pa Hewlett Packard Co New Jersey Div Berkeley Heights N J General Elect Co Semiconductor Prod Dept Bu falo N X General Elect Co Semiconductor Prod Dept Auburn N Y C amp K Components Inc Newton Mass Burndy Corp Norwalk Conn Wagner Electric Corp Tung Sol Div CTS of Beme Inc Chicago Telephone of Cal Inc So Pasadena Calif IRC Div of TRW Inc Boone Plant Boone N C Bloomfield N T Beme Ind General Instrument Corp Rectifier Div Philadelphia Handie Co Inc Camden N J U S Terminals Inc Cincinnati Ohio Hamlin Inc Lake Milis Wisconsin Clarostat Mfg Co Inc Dover N H Thermalloy Co Dallas Texas Hewlett Packard Co Loveland Div Loveland Colo Cornell Dubilier Electronics Div Federal Pacific Electric Co Newark N J General Instrument Corp Semicon ductor Prod Group Hicksville N Y Fenwai Elect Framingham Mass Corning Glass Works Electronic Components Div Raleigh N C Newark N J XUse Code 28480 assigned to Hewlett Packard Co Palo Alto California Table 6 3 Code List of Manufacturers Continued CODE MANUFACTURER ADDRESS Delco Radio Div of General Motors Corp Kokomo Ind Atlantic Semiconductors In Asburv Park N J Fairchild Camera and instrument Corp Semiconductor Div Transducer Plant Mountain View Calif Daven Div Thomas A Edison industries
53. meter indica tion f Raise the temperature to 40 C and allow a half hour warm up g Differential voltmeter indication should change by less than 60 0 mvdc from indication recorded in step e 5 25 Output Stability Proceed as follows a Connect test setup shown in Figure 5 4 b Turn front panel VOLTAGE controls to maximum rated output voltage c Turn front panel CURRENT control until the differential voltmeter indicates 2 0 vdc d Allow a half hour warm up and then record the differential voltmeter indication e After eight hours differential voltmeter indication should change by less than 10 0 mvdc from indication recorded in step d 5 26 COVER REMOVAL WARNING Make certain power supply is off and high voltage capacitors are discharged allow five min utes before removing covers The high voltage present in this power supply can cause injury 5 27 The top and bottom covers are removed by removing both sets of six attaching screws 5 28 TROUBLESHOOTING 5 29 If a fault in the power supply is suspected remove the covers and visually inspect for broken connections burned components etc If the fault is not detected visually proceed to trouble analy sis If the fault is detected visually or via trouble analysis correct it and then perform the perform ance check Paragraph 5 6 If a part is replaced refer to repair and replacement Paragraph 5 39 and to adjustments and calibrations Paragraph 5 41 5
54. mfield Div Princeton Ind 87034 Marco 6 Oak Industries a Div of Oak 776301 TRW Electronic Components Div Electro netics Corp Anaheim Calif Camden N J 872161 Philco Corp Lansdale Div Lansdale Pa 777641 Resistance Products Co Harrisburg Pa 87585 Stockwell Rubber Co Inc 781891 Illinois Tool Works Inc Shakeproof Div m Philadelphia Pa Elgin Ill 879291 Tower Olschan Corp Bridgeport Conn 78452 Everlock Chicago Inc Chicago Ill 881401 Cutler Hammer Inc Power Distribution 784881 Stackpole Carbon Co St Marys Pa and Control Div Lincoin Plant 785261 Stanwvek Winding Div San Fernando Lincoln Mi Electric M g Co Inc Newburgh N Y 882451 Litton Precision Products Inc USECO 78553 Tinnerman Products Inc Cleveland Ohio Div Litton Industries Van Nuys Calif 78584 Stewart Stamping Corp Yonkers N Y 906341 Gulton Industries Inc Metuchen N J 79136 Waldes Kohinoor Inc Lil Es Ni Xe 907631 United Car Inc Chicago Ill 79307 Whitehead Metals Inc New York N Y 913431 Miller Dial and Nameplate Co 79727 Continental Wirt Electronics Corp Ei Monte Calif Philadelphia Pa 1418 Radio Materials Co Chicago Ill 799631 Zierick Mfg Co Mt Kisco N Y 91506 Augat Inc Attleboro Mass 80031 Mepco Div of Sessions Clock Co 91637 Dale Electronics Inc Columbus Neb Morristown N T 916621 Elco Corp Willow Grove Pa 30294 Bourns Inc Riverside Calif 919291 Honeywell Inc Div Micro Switch 810421
55. mplifier across bases of 04 05 is the voltage difference across CURRENT control R21 programming resistor and current monitoring resistor R20 Because the programming current is constant in constant current Operation the voltage input to the differential amplifier varies as the load current through R21 error voltage Capacitor C10 provides gain roll off at high freguencies for stabilitv Diode CR9 fixes the collector voltage of Q5 to eliminate the Miller effect capacitance which is pronounced at high frequencies Voltage divider R23 R24 biases the base of 05 slightly positive to ensure that the Output current can be programmed to zero The col lector output of Q4 is coupled to the diode gate CR12 4 28 DIODE GATE 4 29 Diode gate CR11 CR12 provides an output to the error amplifier base of Q6 that is determined by either the voltage or current input circuit In constant voltage operation CR11 is forward biased and CR12 is reverse biased the reverse is true in constant Current operation Resistor R33 provides small current path for the forward biased diode so that the diode is properly biased when the error signal is small 4 30 ERROR AMPLIFIER 4 31 The two stage O6 and 07 error amplifier provides gain for the voltage and current error signals from the diode gate Stage Q6 is an emitter follower to eliminate the Miller effect Zener diode VRI provides a 6 2 Vdc bias The emitter output of Q6 is coupled via R38 and C
56. ndix Corp Electric Power Div 98291 Sealectro Corp Mamaroneck N Y Eatontown N J 984101 ETC Inc Cleveland Ohio 833301 Herman H Smith Inc Brooklyn N Y 98978 International Electronic Research Corp 833851 Central Screw Co Chicago ML Burbank Calif 835011 Gavitt Wire and Cable Div of 999341 Renbrandt Inc Boston Mass Amerace Esna Corp Brookfield Mass PART NO 0160 2453 0160 0168 0140 0047 0160 0168 0160 0161 0160 0157 0160 0161 0180 1893 0180 1884 0180 0049 0180 0094 0180 0300 0160 0163 0180 0300 0160 0168 0160 2453 0150 0081 0160 0163 0180 1838 1901 0327 1901 0033 1901 0033 1901 0461 1901 0033 1901 0033 1901 0461 1901 0033 AN DESCRIPTION Main Board NOT USED fxd film 0 22uf 80 Vdc fxd film 0 luf 200 Vdc fxd mica 510pf 5 NOT ASSIGNED fxd film 0 1uf 200 Vdc NOT ASSIGNED fxd film 0 01uf 200 Vdc fxd film 4700pf 200 Vdc NOT ASSIGNED fxd film 0 01uf 200 Vdc NOT ASSIGNED NOT USED NOT ASSIGNED NOT USED NOT ASSIGNED fxd elect 1450uf 45 Vdc NOT USED fxd elect 200uf 65 Vdc fxd elect 20uf 50 Vde fxd elect 100uf 25 Vdc NOT USED fxd elect 20uf 16 Vdc NOT ASSIGNED fxd film 0 033uf 200 Vdc fxd elect 20uf 16 Vde fxd film 0 1uf 200 Vdc fxd film 0 22pf 80 Vdc fxd ceramic 0 0luf 500 Vdc fxd film 0 033uf 200 Vdc fxd elect 75uf 16 Vdc rect Si 500 mA 200prv rect Si 200 mA 180prv NOT ASSIGNED rect Si 200 mA 180prv NOT ASSIGNED rect Si 200 mA 1
57. nish or lacquer When replacing components with multiple mounting pins suchas tube sockets electrolytic capa citors and potentiometers it will be necessary to lift each pin slightly working around the components several times until it is free WARNING If the specific instructions outlined in the steps below regarding etched circuit boards without eyelets are not followed extensive damage to the etched circuit board will result 1 Apply heat sparingly to lead of component 2 Reheat solder invacant eyeletand quickly to be replaced If lead of component passes insert a small awlto cleaninside of hole through an evelet i I hole does in the circuit not have an CONDUCTOR SIDE board apply eyelet in heat on com sert awl or ponent side a 57 drill of board If from con lead of com amp ductor side ponent does of board not pass through an eyelet apply Heat to conductor side of board 4 Holdpartagainst board avoid overheating 3 Bend clean tinned lead on new part and and solder leads carefuliv insert WA 3 Apply heat to compo through eyelets or pekan nent leads on correct holes in board side of board as explained zz Gr 2298824 in step 1 LA EMAK 2 BD Ld dads tard ahaha ARL ET ee ed In the eventthat either the circuit board has been damaged or the conventional method isimprac tical use method shown below Thisis especially applicablefor circuit boards without
58. nt i i l 8 OUTPUT TERMINALS l 9 Output power is available via two UG 931 U connectors at the rear of the power supply Mating connectors UG 932 U are supplied with the unit The output terminals are isolated from the chassis and either the positive or the negative terminal mav be connected to the chassis by shorting the center pin and case of the applicable UG 931 U connector or by grounding a wire from the connector to the chassis The power supply is insulated to permit Operation up to 2 000 vdc off ground i e the maxi mum potential between either output terminal and ground shall not exceed 2KV above the maximum rated output 1 10 INSTRUMENT IDENTIFICATION 1 11 Hewlett Packard power supplies are iden tified by a two part serial number The first part is the serial number prefix a number letter combination that denotes the date of a significant design change and the country of manufacture The first two digits indicate the year 10 1970 11 1971 etc the second two digits indicate the week and the letter A designates the U S A as the countrv of manufacture The second part is the power supply serial number a different sequential number is assigned to each power supply starting with 00101 1 12 If the serial number on your instrument does not agree with those on the title page of the manual Change Sheets supplied with the manual or Manual Backdating Changes define the difference between your
59. o 2 000 Vdc off ground floating see Paragraph 3 10 I is not recommended that the power supplv be floated above 300Vrms at frequencies below 500Hz WARNING Serious injurv to personnel can occurif the power supplv chassis is unground ed The warrantv is void if the chassis is ungrounded during operation 3 1 NOTE With the unit on and no load connect ed the transformer will make an audi ble ticking noise This is perfectly normal for this unit and should not be a cause for rejection WARNING When shorting out the output ter minals for any reason make certain the power supply is off and the high voltage capacitors are discharged allow five minutes The high voltage present in this supply can cause injury 3 5 NORMAL 3 6 Constant Voltage To select a constant voltage output proceed as follows a With supply off adjust VOLTAGE thumb wheel controls for desired output voltage output terminals open b Short output terminals then turn on supply and adjust CURRENT control for maximum output current allowable current limit as determined by load conditions Ifa load change causes the current limit to be exceeded the power supply will automatically crossover to constant current output at the preset current limit and the output voltage will drop proportionately In setting the current limit allowance must be made for high peak currents which can cause unwanted crossover Refer to Paragraph 3 17
60. ollows Connect the load resistance value shown in Figure 5 1 100 1 voltage divider and the dif ferential voltmeter to the T connector b Turn front panel CURRENT control fully clockwise maximum c Tum front panel VOLTAGE controls until front panel voltmeter indicates the maximum rated output voltage d The differential voltmeter should indicate Mode 6521A 6522A 6525A Volts de 10 0 2 20 0 4 40 0 8 e Reset front panel VOLTAGE controls until controls indicate exactly the maximum rated out put voltage f The differential voltmeter should indicate Model 6521A 6522A 6525A Volts dc 1020 1 20 0 2 4040 4 5 10 Line Regulation Proceed as follows a Turn front panel CURRENT control fully clockwise maximum b Connect the variable voltage transformer between the input power source and the power sup plv power input Adjust the variable voltage trans former to 104 VAC c Turn front panel VOLTAGE controls until the differential voltmeter indicates maximum rated output d Adjust the variable voltage transformer to 127 VAC e Differential voltmeter indication should change by less than Model 6521A MVDC 0 2 6522A 0 3 6525A 0 5 5 11 Load Regulation Proceed as follows a Turn front panel CURRENT control fully clockwise maximum b Turn front panel VOLTAGE controls until the differential voltmeter indicates maximum rated output c Disconnect load resistance d Differen
61. on necting wires This will minimize mutual coupling effects 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 to reduce noise pickup in addition a 0 1 to 1 0 uf capacitor should be connected between one terminal and the chassis if the supply is floated off of ground The mating connectors for the output terminals are of the UG 932 type HP Part No 1250 0927 and the cable type is RG 59 U HP Part No 8120 0019 Due to the high output voltage of the supply it is important that only this type cabie be used 3 11 If load considerations require that the output power distribution terminals be remotely located irom 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 separately connected to the remote distribution terminals A 0 1 to luf capacitor should be connected across the remote distribution terminals to reduce high frequency coupling and noise NOTE It is recommended that the voltage drop in the connecting wires not exceed 2V If a larger drop must be tolerated please consult a Hewlett Packard field representative 3 12 PARALLEL 3 13 Two power supplies can be connected in paraliel to obtain a com bined output current greater than that available from one supply The total output current is the sum of the
62. onstant Voltage Check reference circuit Paragraph 5 35 Refer to Paragraphs 5 53 and 5 55 for adjustments Power supply going into current limit Check con stant current input circuit Constant voltage loop oscillates Check adjust ment of R7 Paragraph 5 58 Poor Load Regulation Constant Current Check reference circuit Paragraph 5 35 Refer to Paragrapns 5 53 and 5 55 for adjustments Power supply going into voltage limit Check con stant voltage input circuit Constant current loop oscillates Check C10 Table 5 4 Common Troubles Continued High Ripple is Poor Stabilitv Constant Voltage PO pop Poor Stability Constant Current SAR EZ 1a Oscillates Constant Voltage Oscillates Constant Current Output Voltage Does Not Go To Zero Output Current Does Not Go To Zero 5 39 REPAIR AND REPLACEMENT 5 40 Before servicing a printed wiring board refer to Figure 5 5 When replacing semiconductor devices make certain that a mica washer and a good silicone grease Dow Corning silicone grease 3 or equivalent are used for mounting in order to provide good heat conduction to the chassis Check operating setup for ground loops If output is floating ungrounded connect luf capacitor between output and ground unless par ticular application prohibits this Line compensation Paragraph 5 52 Check reference circuit Paragraph 5 35 Check ad
63. pt Irmo S C Bassik Div Stewart Warner Corp Bridgeport Conn IRC Div of TRW Inc Semiconductor Plant Lvnn Mass Amatom Electronic Hardware Co Inc New Rochelle N X Beede Electrical Instrument Co Penacook N H General Devices Co Inc Indianapolis Ind Semcor Div Components Inc Pnoenix Arizona Robinson Nugent Inc New Albanv Ind Torrington Mfg Co West Div Van Nuvs Calif Transistor Electronics Corp Minneapolis Minn CODE NO 07138 07263 07387 07397 07716 07910 07933 08484 08530 08717 08730 98806 08863 08919 09021 09182 09213 09214 09353 09922 11115 11236 11237 11502 11731 12136 12615 12617 12697 13103 14493 14655 14936 15801 16299 MANUFACTURER ADDRESS Westinghouse Electric Corp Electronic Tube Div Elmira N Y Fairchild Camera and Instrument Corp Semiconductor Div Mountain View Calif Birtcher Corp The Los Angeles Calif Svivania Electric Prod Inc Sylvania Electronic Systems Western Div Mountain View Calif IRC Div of TRW Inc Burlington Plant Burlington lowa Continental Device Corp Hawthorne Calif Raytheon Co Components Div Semiconductor Operation Mountain View Calif Breeze Corporations Inc Union N F Reliance Mica Corp Brooklyn N X Sloan Company The Sun Valley Calif Vemaline Products Co Inc Wyckof N J General Elect Co Minia ture Lamp Dept Cleveland Ohio Nylomatic Corp Norrisvi
64. r Fuse holder nut Derline standoff 48 32 Insulator boron nitride Insulator boron nitride Bushing teflon AC Receptacle Capacitor clamp C24 Machine screw Hex nut Solder lug High voltage wire Front chassis Side cover 1 Side cover 2 Chassis Rear Heat sink 6 12 28480 89032 28480 56289 56289 89032 28480 28480 06540 06540 06540 28480 28480 28480 28480 28480 28480 28480 28480 28480 28480 28480 28480 28480 28480 28480 28480 28480 MFR PART NO C17373 012 24B 4586 2A 3 36 132D C8091 632 4 9261PH171 9323A171 93254171 Fig 7 1 Component Locations NOTE MODEL 6525A CONTAINS MORE COMPONENTS THAN MODEL 6522A THE COMPONENTS ARE CR42 53 R65 77 AND R223 226
65. s L4A and C33 L4B and C34 reduce voltage spikes 4 4 PULSE WIDTE MODULATOR 4 42 The pulse width modulator is a gate circuit that opens and closes in response to pulses from the Schmitt trigger and transfers charge from the line voltage bridge and storage capacitor to the high voltage bridge and storage capacitor Initially C19 is charged to approximately 320 volts by the line voltage storage capacitor via R45 CR17 and F3 The first pulse from the Schmitt triggergates CR15 on Current flows from the line voltage storage capaci tor through high voltage transformer TI CR17 L3 and CRIS The voltage across Tl appears as a step function the current is ramp shaped 4 43 When CRIS was gated on it effectively clamped test point 56 to test point 53 neglecting small voltage drops across CR15 and L3 Thus the positive side right side of C19 is pulled down to test point 53 Because the voltage across a capaci tor cannot change instantaneously the negative side left side of C19 must fall a corresponding amount with respect to test point 53 This forward biases CR18 which begins charging C19 through Li in the opposite direction Due to the energy storage of Li C19 is charged to approximately 160 volts CR18 prevents C19 from discharging back into L1 The time required to charge C19 to 160 volts is approximately 120 microseconds 4 44 The next pulse from the Schmitt trigger gates CR16 on The positive side left side of C19
66. s and Betts Co Philadelphia Pa Union Carbide Corp New York N Y Ward Leonard Electric Co Mt Vernon N Y CODE No MANUFACTURER ADDRESS Amperite Co Inc Union City N J Beemer Engrg Co Fort Washington Pa Belden Corp Chicago lil Bud Radio Inc Wilioughbv Ohio Cambridge Thermionic Corp Cambridge Mass Bussmann Mfg Div of McGraw 6 Edison Co St Louis Mo CTS Corp Elkhart Ind LT T Cannon Electric Inc Los Angeles Calif Globe Union Inc Centralab Div Milwaukee Wis General Cable Corp Cornish i Wire Co Div Williamstown Mass Coto Coil Co Inc Providence R I Chicago Miniature Lamp Works Chicago Ill Cinch M g Co and Howard B Jones Div Chicago Ill Dow Coming 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 Ili Elastic Stop Nut Div of Amerace Esna Corp Union N J Erie Technological Products Inc Erie Pa Hart M g Co Hart ord Conn Beckman Instruments Inc Helipot Div Fullerton Calif Fenwal Inc Ashland Mass Hughes Aircraft Co Electron Dynamics Div Torrance Calif Amperex Electronic Corp Hicksville N Y Bradley Semiconductor Corp New Haven Conn Carling Electric Inc Hartford Conn Federai Screw Products Inc Chicago Ill Heinemann Electric Co Trenton N J Hubbeil Harvey Inc Bridgeport Conn Amphenol Corp Amphenol RF
67. s the output terminals Thus the 10 000 ohm resistor shunts the reverse current across the power supply For more informa tion on preloading refer to Paragraph C4 in the Harrison Division Application Manual This manual can be obtained from your local Hewlett Packard Field Sales Office Refer to list at rear of manual SECTION IV PRINCIPLES OF OPERATION TURN ON TURN OFP SCHMITT TRIGGER CIRCUIT 20 VDC BIAS A SUPPLY CURRENT MONITORING SERIES RESISTOR REGULATOR 40 VDC R21 BIAS CURRENT SUPPLY OUTPUT PROGRAMMING RESISTOR VOLTAGE INPUT CKT FROM SCHMITT TRIGGER CIRCUIT PULSE TRANSPORMER VOLTAGE T3 i QUTPUT PROGRAMMING RESISTORS HIGH VOLTAGE PULSE WIDTH BRIDGE MODULATOR AND STORAGE CAPACITOR CAPACITOR VOLTAGE DOUBLER Figure 4 1 Block Diagram 4 1 4 1 BLOCK DIAGRAM DESCRIPTION See Figure 4 1 4 2 The ac input power is applied to auxilliary power transformer T2 and to the line voltage bridge and storage capacitor circuit The auxilliary power transformer provides isolation and power for the turn on turn off circuit and for the 20 Vdc and 40 Vdc bias supplies The line voltage bridge and storage capacitor circuit full wave rectifies and filters the ac input to provide a dc power source for the pulse width modulator 4 3 The high voltage bridge and storage capaci tor circuit in series with the 40 Vdc bias suppiv and the series regulator provide the dc output voltage
68. sitive lead and 53 waveform shown on schema tic diagram If waveform is incorrect CR25 through CR28 R48 R49 or T3 may be defective 4 Waveform across test points 56 positive lead and 53 waveform shown on schemat ic diagram If waveform is incorrect the pulse width modulator may be defective Use standard troubleshooting techniques in conjunction with the normal voltages and waveforms shown on the sche matic diagram to isolate the defect g Using the differential voltmeter proceed as instructed in Table 5 3 Table 5 3 Low Output Voltage Trouble shooting A x aan Mo A l More positive than 20 vdc 18 to 20 vdc 010 or Q11 open Proceed with Step 2 Less than 1 vdc l to 1 1 vdc CR11 or R32 shorted Proceed with Step 3 Less than 6 2 vdc a OlA or 03 open b QIB 02 or R13 shorted Proceed with Step 4 6 2 to 6 8 vdc More negative than 0 vdc a R3 open b QIA open Resistor in voltage control circuit shorted 0 vde 5 38 COMMON TROUBLES Table 5 4 gives the 115 volt 60 Hz cps single phase power input svmptoms checks and probable causes for com and the test equipment listed in Table 5 1 mon troubles The checks should be made using a Table 5 4 Common Troubles Poor Line Regulation Check reference circuit Paragraph 5 35 Refer to Paragraph 5 51 for adjustment Check 20 and 40 vdc bias supplies Poor Load Regulation C
69. ss than 10 0 mvdc 5 21 load Regulation Proceed as follows a Connect test setup shown in Figure 5 4 Close shorting switch b Turn front panel VOLTAGE controls to maximum c Turn front panel CURRENT control until the differential voltmeter indicates 2 0 vdc d Open the shorting switch e Differential voltmeter indication should change by less than 10 0 mvdc 5 22 Ripple and Noise Proceed as follows a Connect test setup shown in Figure 5 4 except replace the differential voltmeter with the AC voltmeter b Turn front panel VOLTAGE controls to maximum rated output voltage c Connect the variable voltage transformer between the input power source and the power sup ply power input Adjust the variable voltage trans former to 127 VAC a Turn front panel CURRENT control until front panel ammeter indicates Model MVDC 6521A 200 6522A 100 6525A 50 e The AC voltmeter should indicate less than 20 mv rms 5 23 ADDITIONAL CONSTANT CURRENT PERFORM ANCE TESTS 5 24 Temperature Coefficient Proceed as follows a Connect test setup shown in Figure 5 4 b Turn front panel VOLTAGE controls to maximum rated output voltage c Turn front panel CURRENT control until the differential voltmeter indicates 2 0 vdc d Insert the power supply into the con trolled temperature oven differential voltmeter remains outside oven Set the temperature to 30 C and allow a half hour warm up e Record the differential volt
70. t is not available contact your Hewlett Packard field office for packing materials and information 2 19 Attach a tag to the instrument which specifies the owner model number full serial number and service required or a brief description of the trouble SECTION III OPERATING INSTRUCTIONS 3 1 CONTROLS AND INDICATORS 3 2 The controls and indicators are illustrated in Figure 3 1 AMMETER VOLTMETER PILOT LIGHT DSi ON OFF VOLTAGE OUTPUT i CURRENT OUTPUT SWITCE THUMBWHEEL CONTROL S1 CONTROLS R21 TURN ON CHECKOUT Turn on supply Use voltage output thumbwheel controls to select output voltage Voltmeter indicates voltage Turn off supply and allow sufficient time for output voltage to approach zero Short circuit output terminals Turn on supply and adjust current output control 4 to select constant current limit Ammeter 5 indicates current Turn off supply wait for output to fall then remove short and connect load Front Panel Controls and Indicators Figure 3 1 3 3 OPERATION 3 4 The power supply can be operated as a single unit normal operation in paraliel or in series No provisions for remote programming or remote sensing has been made due to their limited use and insulation problems at 1 000 Vdc For safety ensure that the power supply chassis is grounded either through power cord or bv other means The operator can ground either output terminal or operate the power supply up t
71. tective clamp in the forward direction for Q15 Diode CR60 provides clamping action to assure that the rigid bias established at the base of Q15 by the collector of Q16 is not sen sitive to ac input line voltage variations line voltage variations affect the collector voltage of 016 4 38 Capacitor C45 and R103 in parallel with R106 form a speed up network to assure rapid turn On and turn off of 016 Capacitor C42 and R101 in parallel with R102 form a speed up network to assure that sharp pulses are developed in pulse transformer 13 Capacitor C39 and R96 in parallel with R95 provide compensation for the voltage rise rate across Qll too fast a rate may cause overshoot in the output of the power supply Capacitor C41 in series with R100 prevent the Schmitt trigger from producing pulse widths less than approximatelv 120 microseconds and from having pulses closer than approximately 500 microseconds The 120 micro second minimum time is required to allow the pulse width modulator commutating circuit to stabilize the 500 microsecond minimum time is required to avoid saturation of high voltage transformer Tl under transient overload conditions 4 39 LINE VOLTAGE BRIDGE AND STORAGE CAPACITOR 4 40 The ac input voltage is full wave rectified by bridge rectifier CR20 through CR23 Storage capacitor C32 is charged to the peak rectified voltage and supplies charge to the pulse width mod ulator when called upon Two filter network
72. the correct fuse is installed GROUND THE INSTRUMENT This product is a Safety Class 1 instrument provided with a protective earth terminai To minimize shock hazard the 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 firmiv 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 terminal will cause a potential shock hazard that could result in personal injury 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
73. ther higher predetermined level the pulse from the Schmitt trigger ends Initially both Q15 and 016 are off by virtue of the bias provided from the col lector of Q11 voltage above lower predetermined level via R95 4 36 When the collector to emitter voltage of Q11 falls below the lower predetermined level Q15 is forward biased by R97 Transistor 015 conducts and causes Q16 to turn on The collector of Q16 goes negative and current via R98 and R99 biases the base of Q15 in the forward direction The primary of pulse transformer T3 is connected to the collector of Q16 via CR67 and R102 The resulting current through T3 causes the pulse width modu ator to initiate the action required to raise the voltage across Oll The voltage across Q11 must rise to a 4 4 level that is higher than the level that was required to forward bias Q15 in order to overcome the rigid forward bias established at the base of Q15 by the current through R98 and R99 When this higher voltage level is reached Q15 becomes reverse biased thus returning both transistors to their non conducting state 4 37 Zener diode VRS and diodes CR64 CR65 and CR66 provide reference voltages Capacitor C40 is a bypass Capacitor C46 acts as a bypass and to assure that when the power supply is tumed on the voltage across VR5 does not rise faster than the voltage across Qll to prevent QIS from being forward biased instead of reverse biased Diodes CR62 and CR63 are a pro
74. tial voltmeter indication should change by less than 0 6 mvdc Oscilloscope may be damaged unless its controls are set for dc input coupling 5 12 Ripple and Noise Proceed as follow s a Disconnect the 100 1 divider and connect proper load resistor to the power supply output usu Pa Gonnect the oscilloscope to the power supply output with the luf 4000wvdc capacitor in series with the oscilloscope lead connected to positive side of supply output c Turn front panel CURRENT control fully clockwise maximum d Connect the variable voltage transformer between the input power source and the power sup ply power input Adjust the variable voltage trans former to 127 VAC e Turn front panel VOLTAGE control until front panel voltmeter indicates maximum rated voltage output f The oscilloscope should indicate less than 150mV p p 5 13 Transient Response Proceed as follows a Connect test setup shown in Figure 5 1 b Turn front panel CURRENT control fully clockwise maximum c Adjust front panel VOLTAGE controls until front panel voltmeter indicates 200vdc d Energize the repetitive load switch from 115 volt 60 Hz single phase power source e Recovery time on the oscilloscope display should not exceed 50us as shown in Figure 5 2 POWER SUPPLY UNDER TEST OSCILLOSCOPE CONTACT PROTECTION NETWORK O pF 4OOV Sa SW NOTE 3 Ry 6521A 6522A 6525A
75. ubleshooting or tions The adjustments and calibrations are per repair and replacement Test points called out in formed using a 115 volt 60 Hz single phase power the procedures are identified on the overall sche input to the power supply 5 12 Tabie 5 7 Adjustment or Calibration Voltmeter Tracking Ammeter Tracking Constant Voltage Programming Current Output Voltage Line Regulation 9 4 VDC Reference Load Regulation 6 2 VDC Reference Load Regulation _ Voltage Output Stability 5 43 METER ZERO NOTE When zer oing the meters be sure to follow the instructions in Paragraph 5 44 exactly This method avoids leaving the pin on the zero adjust screw in con tact with the upper meter spring where it could affect the meter sensitivity and cause the zero adjustment to drift 5 44 Proceed as follows a Turn off power supply and allow five min utes for all capacitors to discharge b Remove top cover Paragraph 5 26 c Rotate meter zero set screw located be hind front panel at top of meter clockwise until the front panel meter pointer is to the right of zero and moving to the left towards zero Stop when pointer is on zero If the pointer overshoots zero continue rotating clockwise and repeat this step d When the pointer is exactly on zero rotate the zero set screw approximately 15 degrees counterclockwise to free the serew from the meter 5 13 i Model Ad
76. ution A single turn potentio meter controls output current METERS Zero to 4kV and 0 50mA front panel meters are included They provide accuracy of 2 full scale Constant Voltage Less than 0 005 or 20 mV whichever is greater Constant Current Less than 1 m CALIBRATION ACCURACY PARD RIPPLE AND NOISE One percent of the voltage control setting 1V At any line voltage and under any load condi tion within rating Constant Voltage Less than 1 mV rms 150mv p p OUTPUT IMPEDANCE Constant Current Less than 500 HA rms DC to 100 Hz cps less than 0 014 E 100 Hz to 1k Hz less than 0 924 TRANSIENT RECOVERY TIME 1xHz to 100kHz less than 0 54 Less than 50 usec is required for output voltage 100k Hz to 1MHz less than 34 recovery to within 0 005 or 20mV whichever is greater following a full load to no load or no load to full load change in output current SIZE 51 Hx 18 Dx 19 W standard rack width TEMPERATURE RATINGS o Operating 0 to 55 C Storage 40 to 75 C WEIGHT TEMPERATURE COEFFICIENT 42 lbs net 63 lbs shipping Output change per degree centigrade change in ambient following 30 minutes warm up Constant Voltage 0 012 plus 1 mv FINISH Constant Current 0 2 plus 0 05 mA Light gray front panel with dark gray case l 2 SECTION II INSTALLATION 2 1 INITIAL INSPECTION 2 11 POWER REQUIREMENTS 2 2 Before shipment the power supply was 2 12 The pow

HP 6525A User's Manual

Contents

Download Pdf Manuals

Related Search

Related Contents