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Service Manual P1 Amplifier

1. TXI n Wapa ame ue MAINS PRESENT DETECT 4 2 516 SOT 323 5V D EMC Shield dud ab Ct R15 Z N 3N3 Esa 10K 250V 2 6 45V D 0W25 R16 R17 E CER EARTH C5 R 115 C om A 1206 2K2 4K7 Ei 220N 1M5 S 3 7 5504 0W25 0W25 EARTH L c2 275 ows FHLDR1 1 T 1 1 1206 1206 N 3N3 PP X2 VR37 T 20mm HLDR FHLDR3 REG2 250V 20mm HLDR c11 DBR1 L4940V5 j CER 100N AS wo2G TO 220 SKTi S SW1 FS1 T6 3AS506 03 N 50V T BULGIN 18 00 0019 0805 5 gt ei 0580 FS2 T6 3AS506 TRIO i 4 4 Gs 1000UF BC849B d TRI 50V 10v SOT 23 MMUN2211LT1 FHLDR2 0805 YK SOT 23 BH 20mm HLDR D6 e ET Basis waco FICA0O5V 3N3 SOT 323 25V 256 250V YK 4 4 4 CER CON3 TX WIRE COLOURS DGND DGND 1 BLUE 3 BROWN MAINS WIRING AND AUXILIARY SUPPLY 4 BLACK es 6 WHITE RLY1A F1CA005V Takamisawa l 250V CER D4 BAS16 VP70V EE VP67V 4 FS4 DBR2 TR3 TX WIRE COLOURS E
2. TRI29 TRI26 1962 2 1 Assembly Drawing LAYER STACKUP MATERIAL FR4 1 6MM THICK NOTES COPPER WEIGHT 2 2 FINISHED 1 Manufacture in accordance with PC A 600F Class 1 HOLE SEES FINISHED SEE NOTE 2 2 Always use NC dril as reference NO undersized finished holes 3 Routed slots are denoted thus GEM ROUTNG SEE NOTE 5 slot width denoted by line width 4 Component pad slot width and plating requirements are indicated COFDERCEAYERS TWO by hole Size and plating Specification of pad in centre of slot MNMUM WDTH 10 ML 5 Mark month year of manufacture on ident layer MNMUM GAP 10 ML 6 Scoring denoted by gt gt gt drill drawing RESIST GREEN DENT WHITE GENERAL TOLERANCES VENDOR CODES SEE NOTE 5 PCB Dims 0 2mm Routing 0 1mm FNSH BEER Al holes 0 1 Omm SCORNG SEE NOTE 6 ALL DMENSIONS IN MILUMETERS UNLESS OTHERWISE STATED TOOLS SORBOTHANE A LEG PREFORMNG FOR POWER TRANSISTORS SORBOTHANE TR126 TR127 TR128 TR129 FACE OF DEVICE SHOULD OVERHANG EDGE BY 0 8mm AND PERPENDICULAR amp VERTICAL
3. OPTO100 N REG2 TO BE SECURED TO HS1 BY HEATSNK CUP REG2 NEED NOT BE INSULATED FROM HEATSINK HEATSINK IS FLOATING ED Waterbeoch Combridge CB5 9PB prawns mE P1 Power Amplifier Main SE Mechonicoll 03_E249 KAL 22 08 03 Text chonge on switch position diog 2 Fiename L962PB_2 pcb 03 E205 KAL 16 07 03 Production Release 1 DRAWING NO 03 111 KAL 16 05 03 Prototype Release B amp R Cambridge Ltd L96 2 2 03 006 KAL 27 01 03 Prototype Release A Pembroke Avenue ECO No INTALS DATE DESCRIPTION OF CHANGE ISSUE Contact Engineer Kevin Lamb Contact Tet 44 0 1223 203243 Printed 26 Aug 2004 Sheets of 10 1 Amplifier main cct board L962AY issue 2 1 Designator Part Description 0 Mee 2 _ Capacitor SM 0805 X7R Ceramic 10 50V 100 Capacitor SM 0805 X7R Ceramic 10 50V 100N Capacitor SM 0805 X7R Ceramic 10 50V 100N Capacitor Boxed Polyester 5mm Pitch 5 100VDC 100N Capacitor SM 0805 X7R Ceramic 10 50V 100N Capacitor SM 0805 X7R Ceramic 10 50V 100N Capacitor SM 0805 X7R Ceramic 10 50V 100N Capacitor Boxed Polyester 5mm Pitch 5 100VDC 100N Capacitor Boxed Polyester 5mm Pitch 5 100VDC 100N Capacitor Boxed Polyester 5mm Pitch 5 100VDC 100N Capacitor Boxed Polyester 5mm Pitch 5 100VDC 100N 1 Amplifier main cct board L962
4. 5V_D R7 I TR3 10 556 0 25 BICOL LED 3mm LED2 5mm GRN LED 5mm SP2 LED SP1 LED LED 5mm DV D SW1 Sw2 SW3 SKHVPB000A SKHVPBO000A SKHVPB000A 1 2 5 2 SW FIX1 FIX2 FIX3 FIX4 FIX5 45V D 77 1 5 753 1 1 E 1 Dia 3 5mm Dia 3 5mm Dia 3 5mm Dia 3 5mm Dia 3 5mm C9 C10 C11 C12 C13 100N 50V 100N 50V X7R DRAWING TITLE P35 P1 Switch PCB R C M Filename 1929 1 0 sch 03 E125 8 05 03 Redrawn LED1 2 swapped Connectors rewired LK1 2 added 1 0 1 l 03_E001 2 01 02 HOLTEK Z1 UPDATED Bi A amp R Cambridge Ltd 1 11 01 LEDS 5 MAINS SWITCH 0 Pembroke Avenue EcoNo INITIALS DATE DESCRIPTION OF CHANGE ISSUE Waterbeach Cambridge CB5 9PB Contact Engineer Kevin Lamb Contact Tel 01223 203243 Printed 13 May 2003 Sheet 1 of 1 DRAWING NO L929CT roi 2 x FD4 4 TOOL TOOL2 TOOL3 TOOL4 L962CT3 2 1962 2 0 Power Amplifier sch SHUTDOWN FIX1 CHASSIS1 Dia 3 2mm FIX3 Dia 3 5mm ITEM QTY L962CT2 2 VIPROT gt VIPROT FIX2 FIX5 FIX6 u Dia 3 2mm Dia3 5mm Dia 3 5mm FIX4 FIX7 FIX8 1 Fe 1 CHASSIS1 CHASSIS2 Dia 3 5mm Dia 3 5mm Dia 3 5mm DRAWING TITLE L962CT2_2 0_PSU and Control Sch PART No DESCRIPTION F006 Clip For SW Profile Hea
5. 9 KoopadO PDeviceDivaMB O Screw Self Tapping Sems NO 4 X 9MM Pan Torx Slot Steel Zinc Plate BLK Bright Washer M5 Form C to BS 4320 O t 1 BLACKCASE PARTS 0 S o E189AYB 1 JEM Black P1 Fascia Complete Assembly Made up of the following parts 8Q006 80006 FMJ Tact Button Spring E083AY FMJ A32 Sub Panel Assy E199AYB Front Panel Assembly Black FMJ P1 E830MC Badge Metal Arcam FMJ E847PM FMJ E894PMB Power FMJ A32 Black HL25AB HL25AB FMJ Tact Button Fastener E933AY MJ I R Window Assy STD SCREENED HA3A04A M C Pan Supa M3X4 Stzp E210AY 4 065 189 80006 E083AY ES ES ee KEE EE El 1 EM Silver P1 Fascia Complete Maqe up of the following see feae Button FMJ A32 Sub Panel Assy DEE E830MC Metal Arcam FMJ een Essam Power FMI ASD Heng HLZSABFMJTadButonFasener O OOO GAY HAS xp hee c E827PK E828PK EB26PK E967SL jSH139 E888PM FMJ I R Window Assy STD SCREENED M C Pan Supa M3X4 Stzp PACKAGING MATERIAL Blanking Plug For 4MM Binding Post MECHANICAL DATA LAYER STACKUP L929PB_2 GTO Top Overloy 2 MATERIAL COPPER WEIGHT HOLE SIZES ROUTING COPPER LAYERS MINIMUM WIDTH MINIMUM GAP RESIST
6. IDENT VENDOR CODES FINISH SCORING 102 FNISHED SEE NOTE 2 SEE NOTE 3 Tw 10 ML 10 ML GREEN WHITE SEE NOTE 4 HASL SEE NOTE 5 o NOTES 1 Manufacture in accordance with IPC A 600F Class 1 2 Always use dril file as reference 3 All routing 2 0mm unless otherwise shown on dril drawing 4 Mark month year of manufacture on ident layer 5 Scoring denoted by gt gt gt on drill drawing GENERAL TOLERANCES PCB Dims 0 2mm Routing 0 1mm All holes 0 08mm ALL DMENSIONS IN MILLIMETERS UNLESS OTHERWISE STATED SNAP OFF AFTER ASSEMBLY c7 Ch conz R9 R11 c2 R26 RIO R25 m 2 Ww 13 gs Yor A TR T5 T rf rf R24 Q TRS TR4 ag 5 H P be on Lal R22 5 E e gie co 5 1 5 2 ca 8 9 ua lt cuT ua FOR USE N C hep Bee 3 uCx SWITCHBOARD N o REV 011 25141 617 819 E SNAP OFF AFTER ASSEMBLY p DRAWNG Contact Engineer Kevin Lomb Contact Tel 44 0 1223 203200 Printed 8 Aug 2003 Sheet 2 of 8 A amp R Combridge Ltd Pembroke Avenue Waterbeach Cambridge CB5 9PB 35 SWITCH BOARD j Filename L929PB_2 PCB 03 E125 8 05 03 Moved Connectors added LK1 2 2 11 01 SW3 CHANGED GROUND PLANES B 24 09 01 PROTOTYPE ECO No NTALS DESCRP
7. o Measure the bias level at test point Con 103 Bias read and confirm the reading is below the absolute max of 35mV ajor component identification FMMT 497 597 t L 849 859 F 1 Base 2 Emitter 3 Collector NC NO CONNECT 74HC32N 1 1929 Blank PCB P35 P1 Amp Microcontroller Board CON1 5V_D 14 3 1 SPARE1 OO OSY SN pio s SRR ON M PEON mer ee DEER HT48R30A 1 6 ee Tee D _ _ DCPROT 1 L019SW po e DIP 28 1 4 j ps ji xp C 4 D P NSPKRZ ON 34 MOLEX R22 R23 R24 R25 5229 NAPB sw 10K 10K 10K 10K ow25 25 0 25 7 0W25 OV D CON2 5V_D 14 H 3 SPARE2 OO OSY pio s ON e TEIN ee 0 027 DEE LINK LK1 IS USED 6111 DCPROT 2 TO CONFIGURE PCB FOR USE 5 OR P1 4 I DL pss i jJ Xr 4 FOR P35 LEAVE LK1 INTACT FOR P1 CUT LINK b Li MOLEX R9 R10 R11 R26 5229 NAPB 10K 10K 10K 10K THERMPROT 0W25 25 0 25 0W25 74HC32N DIP 14 DVD 2 1 4 74HC32N SPKR1 ON DIP 14 c14 2 DCPROT 1 9 J ms i mt Se DCPROT 2 10 74HC32N DIP 14 IC2D IS SPARE1 12 D2 0W25 MF 1N4148 74HC32N DO 35 DIP 14 R18 10K 0W25 STANDBY MF ny TR7 i ES 92 0W25 077 ME on TOOL1 TOOL2
8. 10K Resistor 1206 Surface Mount 0 25W 1 10R Resistor 1206 Surface Mount 0 25W 1 10R Resistor 1206 Surface Mount 0 25W 1 6K8 Resistor 1206 Surface Mount 0 25W 1 6K8 Resistor 1206 Surface Mount 0 25W 1 2 2 Resistor 1206 Surface Mount 0 25W 1 2 2 Resistor 1206 Surface Mount 0 25W 1 100R Resistor 1206 Surface Mount 0 25W 1 330R Resistor 1206 Surface Mount 0 25W 1 330R Resistor 1206 Surface Mount 0 25W 1 100R Resistor 1206 Surface Mount 0 25W 1 100R Resistor 1206 Surface Mount 0 25W 1 100R Resistor 1206 Surface Mount 0 25W 1 100R Resistor 1206 Surface Mount 0 25W 1 100R Resistor 1206 Surface Mount 0 25W 1 100R Resistor 1206 Surface Mount 0 25W 1 100R Resistor 1206 Surface Mount 0 25W 1 18K Resistor 1206 Surface Mount 0 25W 1 18K Resistor 1206 Surface Mount 0 25W 1 4K7 Resistor 1206 Surface Mount 0 25W 1 4K7 Resistor 1206 Surface Mount 0 25W 1 4K7 Resistor 1206 Surface Mount 0 25W 1 4K7 Resistor 1206 Surface Mount 0 25W 1 4K7 Resistor Metal Film 0 25W 1 820R Resistor Metal Film 0 25W 1 6K8 Resistor Metal Film 0 25W 1 6K8 Resistor Metal Film 0 25W 1 6K8 Resistor Metal Film 0 25W 1 6K8 Resistor Metal Film 0 25W 1 6K8 Resistor Metal Film 0 25W 1 100R Resistor 1206 Surface Mount 0 25W 1 12K Resistor 1206 Surface Mount 0 25W 1 12K Resistor Metal Film 0 25W 1 22K Resistor 1206 Surface Mount 0 25W 1 47R Resistor 1206 Surface Mount 0 25W 1 47R Resistor 1206 Surface Mount 0 25W 1 47R Resistor 1206 Surface
9. 5 Each secondary winding to have a full wave 4diode bridge to produce a uF i Vr m s Volt Volt Ohm r m s single DC rail AS shown diagram PRIMARIES 6 way MOLEX MFIT JNR 6 Output Capacitance to be as specified per rail 7 Output voltages to be as specified in table and as shown in diagram 8 Note Transformer to be used in a power amplifer The specified load currents on the high power rails VP58V VN58V represent the effective current drawn when the amplifier is loaded to full rated power 200W into an 8ohm load and operated continuously This load current is not typical of normal operation which is considered to be 1 8th of full rated power 90 degree SECONDARIES 10 way MOLEX MFIT JNR a Voltage on Reservoir Capacitor Vpk ee Vaverage Vmin 10mS 130mm TEST CIRCUIT Vf 1 1V per diode VOUT AC IN DRAWING TITLE POWER TX FOR P1 1 15 230V 03 E240 Reduced VP58V VN58V to 43 0Vac 1 0 Ricostahouatabie 03_E193 esj UL rated sleeving was UL94 VO B 3 N R C N M Filename L926TX_1 0 sch 03_E192 Added note about UL94 V0 sleeving B 2 03 E158 Corrected Schematic Symbol pin numbers B 1 GND A amp R Cambridge Ltd KAL Changed Pri wire colours VP58 and VN58 1V lead out forms B 0 embroke Avenue INITIALS DATE DESCRIPTION OF CHANGE ISSUE Waterbeach Cambridge CB5 9PB Contact Engineer Kevin Lamb Contact 0
10. 1206 Surface Mount 0 25W 1 22K Resistor 1206 Surface Mount 0 25W 1 22K Resistor 1206 Surface Mount 0 25W 1 22K Resistor 1206 Surface Mount 0 25W 1 22K Resistor 1206 Surface Mount 0 25W 1 150R Resistor 1206 Surface Mount 0 25W 1 150R Resistor 1206 Surface Mount 0 25W 1 150R Resistor 1206 Surface Mount 0 25W 1 150R Resistor 1206 Surface Mount 0 25W 1 270R Resistor 1206 Surface Mount 0 25W 1 22K Resistor 1206 Surface Mount 0 25W 1 10K Resistor 1206 Surface Mount 0 25W 1 10K Resistor Carbon Film 2W 5 10R Resistor 1206 Surface Mount 0 25W 1 100K Resistor 1206 Surface Mount 0 25W 1 120K Resistor 1206 Surface Mount 0 25W 1 39K Resistor 1206 Surface Mount 0 25W 1 18K Resistor 1206 Surface Mount 0 25W 1 2K2 Resistor 1206 Surface Mount 0 25W 1 18K Resistor 1206 Surface Mount 0 25W 1 2K2 1 Amplifier main cct board L962AY issue 2 1 Designator Part Deseription s s s C sC C s C S S EE All parts be ordered via spares arcam co uk Pembroke Ave Waterbeach Cambridge CB5 9PB ENGLAND TEL 44 0 1223 203 203 FAX 44 0 1223 863 384
11. TO MNMUM FOR INTIAL POWER UP Z 1 2 SORBOTHANE 3 PLACES COPPER RIVETS 2 PLACES Gj FULL PIECE SORBOTHANE 2 PLACES 2 E d SORBOTHANE D 757 i d res REGI CONI00 CS 2d sm P L H O 2 sm SH1 5w100 l swo tah j d m K AE ef Uo Y Z 1 8 B RI83 2 KI 3 B e c2 N e mn Sp C I e Ho E co m I y c5 SE 8 CE em S AAL Besse 2 OOS C i C130 c4 AREE PO ZC WE Fo Em d i cns D112 R20 C150 foniod 0111
12. include Fig 1 Power amp power supplies Power supply Powers 67v D C VAS stage 58v D C Output driver stage The two sets of supplies are driven from their own secondary windings and bridge rectifier circuits DBR5 and DBR6 Rectify the 58v rails these are smoothed by 20 000uf of capacitance per phase DBR2 and DBR3 are supplying the 70 rails these are dropped to 67 by the Network of R5 R6 R7 R8 and TR3 TR4 TR5 TR6 this is not a regulated supply as the rails need to track the 58v rails under mains power fluctuations Please note The 70 rails are individually fused by 315mA T fuses at locations FS4 and 55 The VAS stage is supplied by higher voltage rails than the following output driver stage this allows the driver stage to fully saturate the output driver stage without the use of a boot strap circuit This supply is exceptionally quite and is critical to the sound quality of the 1 Amplifier Stage The XLR connector at CON100 allows balanced inputs to be applied to the amplifier and CON101 allows for the balanced signal to be daisy chained to a second 1 The signal from CON100 is driven into 100 this is a Balanced to single ended converter it supplies a signal ended output from a single XLR input The IC derives it power supply rails from the 67v rails these are dropped to 15v by the TR100 and TR114 The unbalanced inputs signal arrives at SK
13. of upto 90 degree phase Power supply Control description The mains input is applied via SKT1 Y capacitors C1 and C2 and X capacitor C5 provide filtering and EMC suppression R2 provides a discharge path for the capacitors SW1 allows the selection of the mains voltage that the unit will operate from the main standby transformer TX1 and the main transformer TX2 have duel primary windings these windings are connected in parallel for 115v operation and in series for 230v operation TX1 is powered at all times when a mains voltage is applied to the mains input socket the secondary of this transformer is fused by via FS3 and rectified by diode bridge DBR1 and regulated to 5V by low dropout regulator at location REG2 to provide a constant 5v D supply for the micro Please note the digital supply ground is connected to the chassis ground via a 100 resistor Relay RLY1 provides a means of powering the main transformer for normal operation as apposed to standby operation where only TX1 is powered this relay is under the control of the Micro IC1 and SW3 on the control board the relay contacts of RLY1 are suppressed by C3 and C4 these prevent sparking and increase the relay life span The circuitry around TR10 functions as a mains present detection circuit A C is feed into this circuit before the Bridge network at location DBR1 when mains is present the circuit drives HI via opto coupler TR1 1 Relay 2 is the speak
14. switch TR120 this will intern switch TR110 and TR109 on in either case this causes the optocoupler at location OPTO100B to transmit a fault line signal to the micro The Thermistor RTH100 provides Thermal protection and is connected to the positive supply rails adjacent to the collector leg of the output driver at location TR125 this allow the thermistor to sense the temperature of the output device The output impedance of RTH100 is low when the amplifier is cool typically a few hundred ohms in the event of a thermal overload situation Above 110 c RTH100 will go into a high impedance state this will switch TR121 on and intern this will switch TR111 on and cause OPTO 100C to send a fault line flag to the micro The remaining protection stage is an insulation breakdown detect circuit this is essentially looking for a breakdown of the insulating pad between the output devices and the heatsinks thus 60v path to ground The protection is formed around bridge rectifier package DBR100 this will route current through the LED in optocoupler OPTO 100D in the event that the DGND and AGND ground planes move apart by more than 10v When the transistor in the Opto conducts the thyristor formed by TR112 and TR132 is turned On Once the Thyristor conducts it pulls the SHUTDOWN signal low and turns TR8 Sheet 2 off thus opening both Speaker relays and the Power relay Please note The unit can only be reset once the mains power supply to
15. the unit has been removed and the Amplifiers own power supplies have been given sufficient time to discharge 30 secs The standby transformer of course remains active TR130 asserts the microprocessor fault line DCPROT so that the micro can indicate the fault via the front panel mounted LED Fig 2 Fault line location and operational status Please note Con 4 is the connector between the main board and the display board use Pin 2 of Con 4 as a reference DGND Fault line Location Status D C offset Con 4 Pin 9 LOW 0v VII Prot Con 4 Pin 8 LOW 0v Thermal Con 4 Pin 7 LOW 0v Test Specification Frequency response 8 ohm load Input set to 1v rms 20Hz 20kHz 0 5 dB Distortion THD N OdBR 4 ohm load Input set to 1v rms 20Hz 20Khz lt 0 02 Maximum output into an 8 ohm load Input level set to 1 34 rms 1Khz 180 watts distortion should be below 0 05 THD N Bias setting notes The bias of the P1 is set using an Audio precision audio analysis package and we calibrate the power stage for minimum THD the bench set up procedure follows o Setthe input signal to 150mv rms frequency to 10kHz Induce a 4 ohm load at the speaker output o Rotate preset RV100 clockwise and observe that the THD falls Continue to rotate the preset until the THD falls to a minimum level and just starts to clime again o Switch input signal off and allow the amplifier the Quiesce 30secs
16. 1223 203243 Printed 7 Aug 2003 Sheet 1 of 1 A3 DRAWING NO L926TX Transformer Specification For 100V P1 transformer Arcam Part Number L927TX Material Safety Specification 1 Winding Wire to be Grade 2 130C rating to BS 60317 4 1995 2 Mylar Polyester Insulator 130C Rated 3 Potting Compound PC3502 E135297 M or equivalent Mechanical Specification 1 Centre of transformer to be potted as shown 2 Primary windings connect to 6 way MOLEX connector 39 01 2065 Secondary windings connect to 10 way molex connector 39 01 2105 Use MOLEX pin 44476 3112 MOLEX connectors have pin numbers indicated on them Connectors to be UL94VO rated Note Molex UL94V0 receptacles may be long lead time items Equivalent Conexcon 6740 Series UL94V0 parts may be used 6 Way receptacle 6740 1060 10 Way receptacle 6740 1100 3 Primary wires are enclosed in a common sleeve Secondary wires are enclosed in a common sleeve Use UL rated sleeving 4 All wire lengths in mm Lengths are 5 0 0 5 Please adhere rubber insulating pad to bottom of transformer as shown Electrical Specification 1 Transformer to have dual 100V primaries to allow parallel operation for 100V input 2 Transformer input voltage range 100V 15 15 85V to 115V 3 Transformer to have 5 secondary windings as show in the adjacent drawing 4 Loaded DC voltages specified at 100V AC in with transformer primaries in parrallel 5 Each secon
17. 2 100V SOT 23 L7812CV 20mm HLDR we YK 0W25 p 1206 12V D TO 220 mmm 9 DGND 100V 18V D TRG ii MKS2 VN7OV 2505171 V 67V TRI EE BD179 m DBR4 DS TO 126 ae wo2G E cag SHUTDOWN 1208 VP18VAC2 lt H 2 2 pes SR Ser d 2 2 2 100 25 YK SOT 323 FMMT497 50V C18 BOPROT 1206 m o gt SOT 28 0805 FS6 100N VIPROT 315mA 100V 5504 MKS2 DGND THERM IHERMPROT 45V D SKT3 1 FHLDR6 14 HOSIDEN 10R 20mm HLDR 17715 HSJ 0W25 12 1206 TRIGGER 11 o PRESENT 10 NOI 9 8 gt 9 7 zi mm 1005 AGND_PSU2 SPKR2 ON 6 B Iv Nez 50V So 5 ON 5 _ 0805 STANDBY 4 DZ1 R18 AGND SIG AGND C1 DGND R12 4 ak Sa Ke AGND_PSU1 AGND LS 2p i A 6 Sores 1206 AGND_PSU3 AGND_C2 P2 kr uod BOND MOLEX D T H 5229 NCPB 70R 100MHz CHASSIS2 DRAWING TITLE 03 E249 KAL 22 08 03 Stability mods 2 0 C10 DGND AGND RC B 1009 1 Ampl ifier Main PCB 03 E203 KAL 16 07 03 Production Release VI Limiting changes 1 0 0805 L962CT2 2 0 PSU and Control Sch 03 184 KAL 23 06 03 Changed sorbothane part numbers corrected R179 182 R185 187 CHASSIS 23425 Notes 03 E111 KAL 11 04 03 Corrected Redesigned protection cct and voicing mods amp R Cambridge Ltd 03 E055 KAL 18 02 03 Minor Change to re label gain switch positions ae No INITIALS DATE DESCRIP
18. 23 FKP2 S d EMITTER2 2 4 SIG 0131 07408 1 ow25 1 8 0W25 R192 NF Me Ka Gar TR129 20V SAP15PY OSCON SAP REF101 LM431AIN3 Rug SOT23 TRIG FMMT597 1008 0W25 SOT 28 Ciao CHASSIS 1206 R103 ent C104 C138 Pia BASE2 we W P102 B HOON HOON HON op ous 100V 50 50 wg SP 250v R165 TR114 MKS2 0805 0603 p 22R 1NO ow25 100v AGND SIG 7 SIG sG ps TRI24 1206 AGND PSU3 FKP2 AGND PSU Soen P125100R FMMT597 puc sores 1206 PI26 che 12 R127 0112 HOON lazuF leka LU 100V 100V 7770 WH 100v MKS2 YK Da YK P110 TR104 TR123 uer 81740 T R128 TR102 23 507 89 497 0110 leka AGND SIG SOT 23 AGND PSU AGND PSU uge LE LD E MF DO 15 R134 D101 eus 0123 R136 NF 878 516 HOON ITUF 878 0 25 SOT 323 100V 100v WH 1206 MKS2 YK 11206 247 E g R179 e 5 o RTHt00 OPTO100A 2 OPTO100B s OPTO100C 110DEG PC3Q66Q PC3Q66Q 8 PC3Q66Q OW25 49 5M D MINEFLAT MNIFLAT K MIN FLAT svp 1206 1 16 3 14 5 12 om JSL x JSL s X ma P132 P136 P137 y HOON 507 23 50 IRI71 R119 R172 R121 R180 R122 Si 0805 02104 us ae we ae we 22K BZX84C owes 0W25 owes owes 0W25 ow25 TE 15V 1206 1206 1206 1206 1206 1206 3 FMMT597 SOT 23 mme DGND D DGND SOT23 zum 166 Rit Piz sch KA P146 pe Sua 20K mm 1 Ne Ka 2105 SOT 23 R151 D105 04 25 04 25 owes owes P147 3206 1206 1208 P157 1206 Ae A M s
19. AY issue 2 1 Designator Part Description d s SS e EE Capacitor Boxed Polypropylene 5mm Pitch 100V 5 470 Capacitor Boxed Polyester 22 5mm Pitch 10 63V 6U8 Capacitor SM 0805 NPO Ceramic 200V 5 47PF Capacitor SM 0805 NPO Ceramic 200V 5 47PF Capacitor Boxed Polyester 5mm Pitch 5 100VDC 47N 06 3ASt6W Diode Surface Mount Small Signal BAST6W SOT 23 3ASt6W Diode Surface Mount Small Signal BAST6W SOT 23 1 Amplifier main cct board L962AY issue 2 1 Designator Part 0 ee UT 22 y 222 Resistor 1206 Surface Mount 0 25W 1 10R Resistor 1206 Surface Mount 0 25W 1 3K3 Resistor 1206 Surface Mount 0 25W 1 2K2 Resistor 1206 Surface Mount 0 25W 1 2K2 R6 14222 Resistor 1206 Surface Mount 0 25W 1 2K2 Resistor 1206 Surface Mount 0 25W 1 2K2 Rp 14222 JResistor 1206 Surface Mount 0 25W 1 2K2 Resistor 1206 Surface Mount 0 25W 1 2K2 Resistor 1206 Surface Mount 0 25W 1 2K2 Resistor 1206 Surface Mount 0 25W 1 2K2 Resistor 1206 Surface Mount 0 25W 1 100R Resistor 1206 Surface Mount 0 25W 1 68K Resistor 1206 Surface Mount 0 25W 1 68K Resistor 1206 Surface Mount 0 25W 1 10K Resistor 1206 Surface Mount 0 25W 1 2K2 Resistor 1206 Surface Mount 0 25W 1 4K7 1 Amplifier main cct board L962AY issue 2 1 Designator Part Description s C C C SS r Resistor 1206 Surface Mount 0 25W 1 10K Resistor Carbon Film 1W 5
20. Maximum ambient temperature 50 C aN ee NOMINAL 109 8 7 d Application POWER SUPPLY FOR DIGITAL LOGIC IN AMPLIFIER USING FULL WAVE BRIDGE RECTIFIER AND 3300uF RESERVOIR CAPACITOR QUIESCENT LOAD 100mA DC Voltages shown when used at 100 SAFETY APPROVAL To meet 5415 1 65 DIMENSIONS SHOWN EXCEPT THOSE DETAILING NOTES PIN SPACING ARE NOMINAL ONLY PINS NOT SPECIFIED IN TABLE ON SHEET TWO SHOULD NOT BE INCLUDED ARCAM A amp R CAMBRIDGE LTD m DIGITAL TRANSFORMER EE D z THIRD ANGLE GO E 100V 03_F336 17 12 03 90 ADDED TO DRAWING TITLE BLOCK PROJECTION TOLERANCES UNLESS am ALL DIMENSIONS IN MILLIMETERS ORIGINAL Er ES Er NIS amsa IX 18 09 00 PRODUCTION RELEASE DRAVN REFERENCE BS 308 PART NUMBER AND DRAWING NUMBER L907TX vu Int 3 w scis e v 100V PRIMARY SECONDARY UV ARCAM e T SE PIN AIT ame 1184090 LL ll Q i og 03 E336 17 12 03 A90 ADDED TO DRAWING TITLE BLOCK 32 RENE REA E ES z NTS amsa 1 18 09 00 PRODUCTION RELEASE pE FINISH DRAWN WITH REFERENCE TO BS 308 PART NUMBER AND DRAWING NUMBER L907TX FLEXFOIL FIT USING ITEMS 16 amp 24 END 2 23 FLEXFOIL END 2 1 Mechanical and packing parts list PartNo GENERALNECHANICALPARIS 6 FMJAG2ChasssAssemby O SSC 07
21. Mount 0 25W 1 47R Resistor 1206 Surface Mount 0 25W 1 ORO Resistor Metal Film 0 25W 1 1K5 Resistor Metal Film 0 25W 1 1K5 Resistor Metal Film 0 25W 1 1K5 Resistor Metal Film 0 25W 1 1K5 Resistor Metal Film 0 25W 1 22R Resistor Metal Film 0 25W 1 22R Resistor Metal Film 0 25W 1 1K8 Resistor Metal Film 0 25W 1 1K8 Resistor Metal Film 0 25W 1 1K8 Resistor Metal Film 0 25W 1 1K8 Resistor 1206 Surface Mount 0 25W 1 1 0 Resistor 1206 Surface Mount 0 25W 1 6K8 Resistor 1206 Surface Mount 0 25W 1 1KO Resistor 1206 Surface Mount 0 25W 1 1KO Resistor 1206 Surface Mount 0 25W 1 1KO Resistor 1206 Surface Mount 0 25W 1 1 0 Resistor 1206 Surface Mount 0 25W 1 1KO Resistor 1206 Surface Mount 0 25W 1 1KO Resistor 1206 Surface Mount 0 25W 1 1KO Resistor 1206 Surface Mount 0 25W 1 1KO 1 Amplifier main cct board L962AY issue 2 1 Designator Par Description C s C C C C s S S IS j Resistor 1206 Surface Mount 0 25W 1 1K0 Resistor 1206 Surface Mount 0 25W 1 1K0 Resistor 1206 Surface Mount 0 25W 1 1K0 Resistor 1206 Surface Mount 0 25W 1 22R Resistor 1206 Surface Mount 0 25W 1 1K0 Resistor 1206 Surface Mount 0 25W 1 1K0 Resistor 1206 Surface Mount 0 25W 1 22R Resistor 1206 Surface Mount 0 25W 1 22R Resistor 1206 Surface Mount 0 25W 1 1K2 Resistor 1206 Surface Mount 0 25W 1 1K2 Resistor Metal Film 0 25W 1 150K Resistor Metal Film 0 25W 1 150K Resistor 1206 Surface Mount 0 25W 1 22K Resistor
22. SAP 15PY YON A 5 0 22 Under output driver failure conditions the 0 22 internal emitter resistor will usually go open the resistor should be measured between pins S and E Protection circuit block The P1 Power amplifier incorporates 4 modes of protection these are as follows o Instantaneous VI current limiting o D C offset protection o Over Temperature o Insulation failure The VI current limit circuit is built around TR106 and TR119 they sense the voltage across the 0 22 emitter resistors hence emitter current and the collector emitter current or device power dissipation exceeds a preset limit The circuit is designed to allow large unrestricted currents into loads of 3 ohms and above but limit the current into a short circuit or very low impedance loads C141 C142 and R162 R163 form 2 2ms time constant which will allow larger transients of current delivery for a few milliseconds to ensure that the amplifier has a sufficiently large transient capability to drive difficult loudspeaker loads TR106 senses positive current surges and TR119 senses negative surges these intern activate TR107 and switch the optocoupler OPTO100A this fault notification is sent to the microcontroller and the output relay is switched off to protect the amplifier loudspeaker coils The D C offset protection is built around TR108 and TR109 a positive D C offset will switch TR108 a negative D C offset will
23. SS Kee 1206 WEIT P139 507 323 bes R187 FMMT497 THERMPROT RI P135 TR107 TR108 SOT 23 10K 39K IR107 DZ105 x owes 0 25 E eg 497 mmer 1206 41206 1008 025 04 25 E 1206 SOT 23 SOT 28 OUTPUT 1206 50 28 zl Over temperature sensing AGND PSU3 mm R108 DZ106 MMUN2111LT1 SOT 23 am Weg TRI20AGND PSUS pis 1206 507 23 597 22K P156 M oie 0W25 nah 50723 DBR100 1206 W02G ie pus Gig miss 2 SHUTDOWN gt R167 R113 2 oe 55 R119 1000 BC859B 100R 25 P129 Prat 151 Ri59 DS n EMMI 1206 p142 61206 0 EN z a 55723 owes R130 AGND PSUS 50 44 AKO ous 1206 eK W 1 0 ms 0805 pus a 1208 155 04 25 nuer MINEFLAT MMUN2211LT1 1206 R156 R160 507 23 497 SOT 23 1K0 2Ko 0 SOT23 Ko 04 25 Rizo 1206 004 25 1206 1206 1 P144 M P158 BZX84C o DCRD Instant SOA limiting Sores 60V DC Output Fault Detect R117 R114 115 1008 j VOS NOS NDS DRAWING TITLE P1 Amplifier Main PCB E249 KA 220803 Stability mods 20 1206 41206 1206 E203 KAL 160703 Production Release VI Limiting changes 10 v D103 Filename 1962 3 20 Power Amplifier sch EtB4 KAL 230603 Changed sorbothane part numbers corrected R179 182 R185 187 BA BASE K 23425 Notes KA 11 0403 Corrected CON4 Redesigned protection cct and voicing mods P119 pang 507 323 A amp R Cambridge Lt
24. Service Manual Issue 1 0 P1 Amplifier 7 77 13 Bringing music amp movies to life Contents List Circuit description Circuit diagrams o L929AY switch PCB o L962AY amplifier main PCB Transformers o L929TX 115 230VAC toroidal o L927TX 100VAC toroidal o L907TX 100VAC frame Exploded view diagram Mechanical amp packing parts list Circuit board silk screen amp parts list o L929AY switch PCB o L962AY amplifier main PCB P1 Amplifier circuit description by A Moore Product description The 1 has been has been designed to provide unsurpassed sound quality the main design features are as follows Gain switchable between Arcam gain and THX gain 29dB closed loop a 0dB signal equates to 100 watts into 8 ohms o Input switchable between unbalance phono and balance XLR amp is capable of producing gt 180 watts of sinusoidal output into an 8 ohm load and greater than 300 watts into a 3 2 ohm load subject to thermal dissipation limits Relay coupled for silent on off operation o Opto isolated fault and control lines to the control PCB o DC coupled signal path with integrating servo to remove residual DC errors o Instantaneous safe operating area protection o Exceptionally low harmonic and intermodulatiion distortion o Flatfrequency response o Fastand asymmetric slew rate o High damping factor o Unconditionally stable into loads
25. T100 the selection between the two input options is accomplished by SW 100 selected signal is clamped 5v3 by the series Zeners at location DZ103 and DZ104 this is to prevent damage to the input of op amp 200 due to leaky source signal or electrostatic discharges SW101 allows for the selection of two gain settings these are 28 3 for THX and 37 5 for the Arcam setting The roll off setting is 340Khz The main power amplifier circuit is a classic current feed back design and can be thought of as a large current feed back op amp the topology is a refined high power output variant of the A90 P7 design Op amp 101 is configured as a non inverting amplifier with a gain of 2 It s purpose is to provide current outputs via it s own power supply pins and a current input via it s output pin the Op amp performs the voltage to current conversion 1 and phase splitting necessary to drive the voltage gain stage The current feed back occurs because the output of IC101 drives into 44 ohm load formed by the two 22 ohm resistors R142 and R143 down to ground the power Cont supply currents half wave rectified versions of the drive current of the amplifier This causes the voltage gain which is buffered and passed on to the outputs The feedback from pin 1 of IC101 acts to reduce the gain of the amplifier when this current is roughly equal to the current required to drive the input signal into 44 oh
26. TION OF CHANGE ISSUE Cambridge 5 9 Contact Engineer Kevin Lamb Contact Tel 01223 203243 Printed 22 Aug 2003 Sheet 2 of 3 DRAWING NO L962CT1 AGND ae Ven ji R125 L a Zoe R135 NF eks Ho 478 04 25 100V 100v WH MKS2 YK 1206 105 2 0108 R126 C120 SIG AGNO Fan AGNO PSU1 KH 27 200 VP58V TRio0 eke mu P106 TR117 DO45 0 25 100v a YK TRIS 887 FMMT597 23 AGND PSU SOT 28 15VD Rigo FMMT497 0118 Zon Diti 50723 Ei cio Jo E HOON 1N4003 Gegend 100N Jon 100V 0041 sos 00425 rd 50 TRI22 MKS2 S 6505 1206 P113 a
27. TON OF CHANGE ISSUE 1 Amplifier display cct board 1929 issue 2 0 awata r r Capacitor Ceramic 5mm Pitch 50V 10 100nF Capacitor Ceramic 5mm Pitch 50V 10 100nF Resistor Metal Film 0 25W 1 10K Resistor Metal Film 0 25W 1 10K Resistor Metal Film 0 25W 1 10K Resistor Metal Film 0 25W 1 10K Resistor Metal Film 0 25W 1 10K Re H30 Resistor Metal Film 0 25W 1 10K Resistor Metal Film 0 25W 1 10K IR8 1H310 Resistor Metal Film 0 25W 1 10K bo 1H310 Resistor Metal Film 0 25W 1 10K Resistor Metal Film 0 25W 196 10K Resistor Metal Film 0 25W 196 10K Resistor Metal Film 0 25W 196 560R Resistor Metal Film 0 25W 1 560R Resistor Metal Film 0 25W 196 330R Resistor Metal Film 0 25W 1 180R Resistor Metal Film 0 25W 196 100K Resistor Metal Film 0 25W 196 10K Resistor Metal Film 0 25W 196 10K Resistor Metal Film 0 25W 1 470R Resistor Metal Film 0 25W 196 470R Resistor Metal Film 0 25W 1 470R Resistor Metal Film 0 25W 196 10K Resistor Metal Film 0 25W 196 10K Resistor Metal Film 0 25W 196 10K Resistor Metal Film 0 25W 196 10K Resistor Metal Film 0 25W 196 10K MECHANICAL DATA SET VOLTAGE SELECTOR TO SUIT NPUT VOLTAGE REQUIREMENTS INLET TO BE SECURED TO PCB BY SET PRESET FULLY gt ANTICLOCKWISE AFTER BOARD ASSEMBLY TO ENSURE Iq 5 SET
28. d 03 055 KAL 180203 Minor Change to re label gain switch positions At ee EGONs NAS DATE DESCRIPTION OF CHANGE SE Cambridge CBS 9PB Contact Engineer Kevin Lamb Contact Tel 01223 203243 Printed 22 Aug 2003 Sheet 3 of 3 DRAWING NO L962CT 2 120 dia 3 Transformer Specification For 115 230V P1 transformer z Connector Latch SECONDARIES me COUNTERBORE DIA 25mm BLACK Ww Lid T PRIMARIES BROWN Arcam Part Number L926TX Material Safety Specification 1 Winding Wire to be Grade 2 130C rating to BS 60317 4 1995 2 Mylar Polyester Insulator 130C Rated 6 way 10 way 3 Potting Compound PC3502 E135297 M or equivalent Mechanical Specification Pin outs of Molex connectors As viewed looking down at the end the wires enter the connector 40mm 50mm 78mm 1 Centre of transformer to be potted as shown YELLOW 2 Primary windings connect to 6 way MOLEX connector 39 01 2065 Secondary windings connect to 10 way molex connector 39 01 2105 Use MOLEX pin 44476 3112 MOLEX connectors have pin numbers indicated on them Connectors to be UL94VO rated 6 Way Molex 10 Way Molex BLUE Note Molex UL94V0 receptacles may be long lead time items 10 50 8Vac Equivalent Conexcon 6740 Series UL94V0 parts may be used SCREEN WIRE GREEN YELLOW 6 Way receptacle 6740 1060 10 Way receptacle 6740 1100 face of max height tra
29. d a W02G c22 RS 2SA1930 C34 1 GREEN 5504 EH TO 220 E 2 YELLOW d 2 Pur GE ORANGE FH DRA i 100V 0 25 100V 4 RED C14 YK 1206 8 5 WHITE 4 H p vP70VAC1 bg 4 2 7 7 VIOLET 100V R6 TRA VN58VAC1 lt FZ p vP18VAC2 Ee agua MKS2 FMMT497 1 6 9 BROWN VP58V Ga SOT 23 VN58VAC2 lt I3 p VP18VAC1 10 BLUE T 0 25 DBRS 4 1206 MOLEN GBUBD 44472 C24 25 R1 c28 c30 R1 1 3 EH 2 VP58VAC1 lt 2 2 10 000UF HOK TUE eet AMPLIFIER 1W 100 25 45V D 12V D MUTING C15 MKS2 1206 Gi T RELAY HOSIDEN D 516 100 AGND C1 SOT 323 MKS2 RLY1C Qon VP58VAC2 lt Takamisawa AK 07 G2R 1 E 12VDC AK 08 NCT AGND C2 T 1 F1CA005V BAS16 BAS16 ale aly l SOT 323 SOT 323 E DBR6 AGND PSUS AGND PSU2 AGND Fa GBUSD P 026 027 29 ca ee peo TE 02 516 C6 VN58VAC1 lt 2 2 10 000UF 10 0000 oK ENBZUF 100 SOT 323 100P 7V 71V 1W 100V 100V 100V 0W25 P5 R9 Ri ES 100V C16 MKS2 1206 5V D a 2 0805 1 1 TR7 K2 2ko 6 EMCGND 100 R7 FMMT497 0W25 FMMT497 100v d TRS R10 Sor23 1206 SOT 28 1206 d EE 5 V 58V B FMMT597 1 e SOT 23 2 4 0 25 FS5 DBR3 aes 1008 1206 T315mA T W02G c23 c35 S504 E R8 E VN70VAC1 lt 2 ENHH000UF E 00UF FMMT497 REG1 FHLDR5 100V 2K
30. dary winding to have a full wave 4diode bridge to produce a single DC rail AS shown in diagram 6 Output Capacitance to be as specified per rail 7 Output voltages to be as specified in table and as shown in diagram 8 Note Transformer to be used in a power amplifer The specified load currents on the high power rails VP58V VN58V represent the effective current drawn when the amplifier is loaded to full rated power 200W into an 8ohm load and operated continuously This load current is not typical of normal operation which is considered to be 1 8th of full rated power d Voltage on Reservoir Capacitor z Connector Latch 1mm 6 10 Pin outs of Molex connectors As viewed looking down at the end the wires enter the connector BLUE 10 8 acs BLACK 1 RED e s BRowN ORANGE 5 H8 stack yELLow 44 e 2 BLUE WHITE GREEN s 5 corey Secondary Winding Voltage and Current Specs Bridge Rectifier Vf diode 1 1V per leg 2 2V Total ideal TX assumed AC Winding Capacitor Label Cout Effective DC Load Current Secondary Voltage uF Vrms 10mS TEST CIRCUIT Vf 1 1V per diode AC IN VOUT RL see above table GND AR Wires to exit from near top of TX Such that wires do not obstruct lid Note Lid is only 1mm abo
31. e C135 JaB1740 AGN SIG AGND PSU 507 89 4 lw Il AGND Fan vol Ne GUB c139 1 AGND SIG AGND PSUI Mes E gi BASE w REF Ha WH 1 1 C136 gt AGND SIG TR101 op OW25 108 107 1206 250 17 497 R175 R177 146 bauen kaum 100 400UF 507 23 ISOT 23 SOT 23 so mm C137 NF 1508 1508 d TR127 0805 CFNE R101 DCS DCS 200V SAP15NY 1 1206 1206 0805 d 50V ig R168 450 AOR OW25 0603 eege 12 118 11018 owes EMITTERI 18100 si TLo72cD MF GP PRECISION 04 25 50 8 1206 R152 SWI00A SW100B SW101A SwioiB SPUN191400 SPUN191400 SPUN191400 SPUN191400 ai owes oMi No oM Trim output stage Iq 128 SELECT XLR 9 et ol m P7 GAIN ol a M k e eS W P108 1 0 leasure Iq 1100 SELECT PHONO ARCAM GAIN 0133 134 0 25 202 Not Noe Not SC mmo C D104 mg 1 wei 5 e contos ma Cus uN Boon r 1 D RLY2A TLO72CD 100V 20v SOT 323 100V 20 2 sos MKS2 MKS2 OSCON T R138 4 Se R183 e 2 4 Se KS HARWIN N L R142 1k5 0 25 ue 20 973 108 2 Omron SKT100 228 MF CF G2R 1 E 12VDO KUNMING R132 ow25 R184 51 R144 R154 GOLD MF ART ae R169 2W AGND Fan owes R143 1 8 OW25 1k8 OW25 dd MF 2R MF hem R155 AGND LS We R140 R141 Ge E MF 1 jiko C150 DZ101 EE C102 owes AN NF 15 OW25 15 OW25 1206 100v 1 om ZX84C kon AGND SG Weg MF ME MKS2 2 84 NF 100v AGND Fan een 2i SOT
32. e constant of 0 5 seconds Any D C offset at the output of the amplifier will cause the output if the op amp to go negative increasing the current in the negative supply pin and thus pulling the output down to ground vica versa D108 protects the inverting input of the op amp under fault condition TR103 provides a 4 7v bias voltage to allow the following pre driver stage to operate in Class A TR123 and TR125 form a Class A pre driver emitter follower stage to boost the current gain and isolate the transresistance stage from the output transistors TR105 and TR118 act as a 30mA current limit and prevent the destruction of TR123 and TR125 under a fault condition R109 R164 R110 and R165 loosely decouple the emitters of TR123 and TR125 from the output stage TR128 TR129 and TR126 TR127 are Sanken SAP 15N and SAP 15P Bi polar output drivers RV100 is the Bias adjust preset D104 protect the Output drivers from destruction if RV 100 goes open circuit C144 to C147 provide local R F stability and prevent oscillation D111 and D112 are catch diodes to reduce the effects of back EMF from the loudspeaker coils load R164 R183 C150 and L100 form the Zobel network these components ensure that the amplifier sees a constant load of 4 7 ohms at high at very high frequencies and improve stability reduce H F noise L100 and R183 decouple the load at high frequencies to ensure amplifier stability into capacitive loads SAP 15NY
33. er output control relay this is used to prevent clicks and pops at power power down and to disconnect the speaker output under a fault condition this relay is controlled by the Micro at location IC1 as the P1 has no manual speaker switching capabilities the micro will automatically initialise the speaker relay 3 seconds after power up the control line SPKR1 on pin 5 of CON 4 switches high to switch the relay ON via TR9 1 has two trigger inputs these applied by SKT2 and are wire OR ed by D5 and D6 The single trigger signal is clamped to 4v7 by DZ1 and fed to the control card by CON4 Applying a 12v trigger signal to either or both trigger inputs on the SKT2 instructs the microcontroller to enable or disable the power amplifier The trigger will be seen as a HI line on Pin 11 of CON 4 The P1 also provides two 2 triggered outputs These are current limited 12v D C levels which are used to provide trigger signals to other units within the customer s installation The 12v output is present when transformer 2 is live i e when the unit is not in standby TX2 has a Low voltage secondary winding that supplies the trigger outputs only via bridge rectifier DBR4 this is fed into REG1 7812 regulator TR1 and TR2 offer a 60mA current limit for both trigger outputs and the entire circuit stage is fused by FS6 T315mA in case of overload The 1 utilizes a fairly unique main power amp power supply configuration these
34. m s equilibrium is reached and the closed loop gain is defined The output stage provides the vast majority of the current required to drive the 44 ohm load The op amp only needs to provide a very small error current to give the required voltage magnification Transistors TR101 and TR116 are common base amplifiers their purpose is to provide the 15v rails necessary to drive the op amp whilst allowing the power supply currents that are drawn to pass through into the Wilson current mirror stage this is formed by PNP transistors TR102 TR104 and TR122 the NPN mirror is formed by TR115 TR117 and TR122 TR103 combines the two current mirrors to provide a very high gain current to voltage transresistance gain stage roughly 80dB at low frequency C114 and C132 with R149 R150 combine to give a open loop pole at roughly 10Khz and a corresponding open loop zero around 500Khz This allows for good time domain performance and clean square wave reproduction with no sign of ringing or overshoot Diodes D100 and D101 act to limit the current through TR115 and TR112 if the input current exceeds 14mA the diodes conduct and the transresistance stage becomes a constant current source killing the open loop gain and preventing damage to the transistors 101 forms a D C intergrating servo Its purpose is to remove residual D C errors due to slight device mismatch and component tolerances It is configured as an inverting intergrator with a tim
35. nsformer Wires to exit from near top of TX POTTING COMPOUND Such that wires do not obstruct lid Note Lid is only 1mm above top 7mm DIA HOLE Rubber insulating pad to have 7mm minimum diameter hole through centre 8 acs BLACK 14 35Vac 18 VIOLET Rubber insulating pad 1 3 Primary wires are enclosed in a common sleeve Secondary wires are enclosed in a common sleeve Use UL rated sleeving RED e s BRowN ORANGE 5 H8 stack yELLow 44 e 2 BLUE GREEN s 5 corey WHITE 4 All wire lengths in mm Lengths are 5 0 0 5 Please adhere rubber insulating pad to bottom of transformer as shown Electrical Specification 1 Transformer to have dual 115V primaries to allow parallel operation for 115V input and series operation with 230V input 2 Transformer input voltage range 115V 18 14 97 5V to 132 5V Secondary Winding Voltage and Current Specs Bridge Rectifier Vf diode 1 1V per leg 2 2 Total 3 Transformer to have 5 secondary windings as show in the adjacent ideal TX assumed drawing SCREEN WIRE 4 Loaded DC voltages specified at 230V AC in with transformer primaries AC Winding Capacitor Effective DC Secondary Capacitor Capacitor Capacitor Load Resistor Secondary in series Label Cout Load Current Voltage Peak Voltage Min Voltage Average to simulate Winding r m s Vmin Voltage Load RL Current
36. tsink Fuseholder Cover For 20mm Fuseholder Fuseholder Cover For 20mm Fuseholder Fuseholder Cover For 20mm Fuseholder Fuseholder Cover For 20mm Fuseholder Fuseholder Cover For 20mm Fuseholder Fuseholder Cover For 20mm Fuseholder Blank PCB P1 Amplifier Main Board Pad Damping 15x6x3MM Sorbothane Pad Damping 7 5x6x3 Sorbothane Earth Lead Assy 75 FIX9 Dia 3 5mm FIX11 Dia 3 5mm FIX10 Dia 3 5mm FIX12 Dia 3 5mm P1 Amplifier Main PCB Filename L962CT1_2 0 Sch 03_E111 03 055 23425 A amp R Cambridge Ltd Pembroke Avenue Waterbeach Cambridge CB5 9PB Contact Engineer Kevin Lamb FIX13 Dia 3 5mm FIX14 Dia 3 5mm 03_E249 03_E203 03_E184 Contact Tel 01223 203243 NOTES E EES amp pe 18 02 03 Minor Change to re label gain switch positions ISSUE Printed 22 Aug 2003 Sheet 1 of 1 DRAWING NO L962CT1 NEUTRAL
37. ve top face of max height transformer Capacitor Peak Voltage 2 120 dia 3 SECONDARIES BLACK COUNTERBORE DIA 25mm Lid PRIMARIES BROWN 40mm 50mm 78mm max YELLOW 6 Way Molex 10 Way Molex 50 8Vac N POTTING COMPOUND GERS SCREEN WIRE GREEN YELLOW Rubber insulating pad to have 7mm minimum diameter hole through centre o 14 35Vac Rubber insulating pad VP18V VIOLET SCREEN WIRE Load Resistor to simulate Load RL Ohm Capacitor Min Voltage Vmin Volt Capacitor Average Voltage Volt Secondary Winding r m s Current A r m s PRIMARIES 6 way MOLEX MFIT JNR 90 degree SECONDARIES 10 way MOLEX MFIT JNR 130mm Ge Rates visa wem enne es ennen em ema us Lae ear LAE ARCAM Co A amp R Cambridge Ltd 03_E006 KAL Prototype Release Pembroke Avenue Waterbeach INITIALS DATE DESCRIPTION CHANGE Cambridge CB5 9PB Kevin Lamb Contact Tel 01223 203243 Printed 7 Aug 2003 Sheet 1 of 1 A3 DRAWING NO L927TX Contact Engineer ISSUE ELECTRICAL SPECIFICATION MECHANICAL DETAILS 1 FREQUENCY 50 60Hz a Regulation AC load current b Continuous VA rating 4VA 0 100V C Voltage unbalance PIN VIEW 4 GENERAL o Magnetic radiation VERY LOW amp CONSISTENT Acoustic noise THE DEVICE SHOULD BE DESIGNED TO BE AS QUIET AS POSSIBLE

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