Arcam-P1-Service-Manual 电路图 维修手册.pdf

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1、Service Manual P1 Amplier Issue 1.0 ARCAMARCAM Bringing music the selection between the two input options is accomplished by SW100. The 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 IC200, due to leaky source sign

2、al 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-am

3、p the topology is a refined high power output variant of the A90/P7 design. Op-amp IC101 is configured as a non-inverting amplifier with a gain of 2. Its purpose is to provide current outputs (via its own power supply pins) and a current input via its output pin, the Op-amp performs the voltage to c

4、urrent conversion (I-V) and phase splitting necessary to drive the voltage gain stage. The current feed-back occurs because the output of IC101 drives into a 44 ohm load formed by the two 22 ohm resistors R142 and R143 down to ground, the powerCont/ supply pin currents are half wave-rectified versio

5、ns 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-ohms equilib

6、rium 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 ampli

7、fiers 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

8、. 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 ti

9、me 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

10、loop gain and preventing damage to the transistors. IC101 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 time constant of 0.5 seconds. Any D.C offset at the outpu

11、t 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 (and vica versa). D108 protects the inverting input of the op-amp under fault condition. TR103 provides a 4.7v bias voltage to allow the

12、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 u

13、nder 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 RV100 goe

14、s 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

15、 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 15NYSAP 15PY S-E 0.22 Ohm SAP Under output driver failure conditions the 0.22 internal emitter resistor will usu

16、ally 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 ci

17、rcuit 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

18、 limit the current into a short circuit or very low impedance loads. C141, C142 and R162, R163 form a 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” lo

19、udspeaker 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 offse

20、t protection is built around TR108 and TR109 a positive D.C offset will switch TR108, a negative D.C offset will 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

21、 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 hu

22、ndred 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 detec

23、t 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 D

24、GND 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. Pleas

25、e note: The unit can only be reset once the mains power supply to 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 mi

26、cro 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 lineLocationStatus D.C offsetCon 4 Pin 9LOW (0v) V/I ProtCon

27、 4 Pin 8LOW (0v) ThermalCon 4 Pin 7LOW (0v) Test Specification Frequency response. 8-ohm load Input set to 1v rms 20Hz 20kHz = +/- 0.5 dB. Distortion. THD+N 0dBR 4-ohm load. Input set to 1v rms. 20Hz 20Khz = 0.02% Maximum output into an 8-ohm load. Input level set to 1.34 rms 1Khz = 180 watts distor

28、tion 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 Set the input signal to 150mv rms, frequency to 10kHz. Induce a 4-ohm load at the speak

29、er 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 o Measure the bias level at test point Con 103 (Bias r

30、ead) and confirm the reading is below the absolute max of 35mV. Major component identification. FMMT 497/597 BC849/BC859 1=Base 2=Emitter 3=Collector TLO 72 SSM2143 74HC32N ISSUE DRAWING NO. DRAWING TITLE DATE Filename: ECO No.DESCRIPTION OF CHANGE L929CT_1.0.sch P35 / P1 Switch PCB Contact Engineer

31、: L929CT 13-May-2003 INITIALS Printed:11Sheetof Notes: Contact Tel:(01223) 203243Kevin Lamb A & R Cambridge Ltd. Pembroke Avenue Cambridge CB5 9PB Waterbeach ARCAM A3 STANDBY SPKR1 ON SPKR2 ON THERMPROT 1 VIPROT 1 DCPROT 1 AC PRESENT TRIGGER REMOTE +5V_D 0V_D 0V_D 0V_D DCPROT VIPROT SP2 LED PWR GRN

32、PWR RED SP2 SW SP1 SW SPKR2 ON SPKR1 ON STANDBY PWR SW REMOTE TRIGGER AC PRESENT SP1 LED THERMPROT THERMPROT 1 THERMPROT 2 VIPROT 1 VIPROT 2 DCPROT 1 DCPROT 2 DCPROT VIPROT THERMPROT 0V_D +5V_D SP1 LED SP2 LED PWR RED PWR GRN PWR SW SP1 SW SP2 SW +5V_D 0V_D +5V_D SPKR1 ON SPKR2 ON THERMPROT 2 VIPROT

33、 2 DCPROT 2 0V_D +5V_D 0V_D +5V_D 0V_D 0V_D 0V_D 0V_D SPKR1 ON SPKR2 ON STANDBY JR1/11/01LEDS TO 5MM AND MAINS SWITCHB.0 WAF2/01/02HOLTEK, Z1 UPDATEDB.103_E001 1 2 3 4 5 6 7 8 9 10 11 12 13 14 CON1 MOLEX 5229-NAPB 1 2 3 4 5 6 7 8 9 10 11 12 13 14 CON2 MOLEX 5229-NAPB STANDBY AC PRESENT TRIGGER REMOT

34、E TR5 BC546B TO-92 TR6 BC546B TO-92 TR7 BC546B TO-92 TR1 BC556B TO-92 TR2 BC556B TO-92 TR4 BC556B TO-92 TR3 BC556B TO-92 R1 10K 0W25 MF R2 10K 0W25 MF R3 10K 0W25 MF R4 10K 0W25 MF R5 10K 0W25 MF R6 10K 0W25 MF R7 10K 0W25 MF R8 10K 0W25 MF R12 560R 0W25 MF R13 560R 0W25 MF R14 330R 0W25 MF R15 180R

35、 0W25 MF R19 470R 0W25 MF R20 470R 0W25 MF R21 470R 0W25 MF R17 10K 0W25 MF R18 10K 0W25 MF R9 10K 0W25 MF R10 10K 0W25 MF R11 10K 0W25 MF R22 10K 0W25 MF R23 10K 0W25 MF R24 10K 0W25 MF C14 100UF 25V YK C6 100UF 25V YK C7 100UF 25V YK C8 100UF 25V YK C5 10UF 50V YK D1 1N4148 DO-35 D2 1N4148 DO-35 R

36、16 100K 0W25 MF 1 2 3 IC2A 74HC32N DIP-14 4 5 6 IC2B 74HC32N DIP-14 9 10 8 IC2C 74HC32N DIP-14 12 13 11 IC2D 74HC32N DIP-14 VCC 14 GND 7 IC2E 74HC32N DIP-14 C9 100N 50V X7R C10 100N 50V X7R C11 100N 50V X7R C12 100N 50V X7R C13 100N 50V X7R C2 100N 50V X7R C3 100N 50V X7R C4 100N 50V X7R 1 FIX1 Dia

37、3.5mm 1 FIX2 Dia 3.5mm 1 FIX3 Dia 3.5mm 1 FIX4 Dia 3 5mm 1 FIX5 Dia 3.5mm C1 100N 50V X7R 1 2 3 X1 4 00MHz SIL-3 LED1 5mm GRN LED 5mm LED2 5mm GRN LED 5mm 1 2 SW1 SKHVPB000A 1 2 SW2 SKHVPB000A 1 2 SW3 SKHVPB000A 0V_D LK1 0R0 0W25 MF PB5 1 PB4 2 PA3 3 PA2 4 PA1 5 PA0 6 PB3 7 PB2 8 PB1 9 PB0 10 VSS 11

38、 (TMR)/INT 12 PC0 13 PC1 14 PC2 15 PC3 16 PC4 17 PC5 18 RES 19 VDD 20 OSC1 21 OSC2 22 PA7 23 PA6 24 PA5 25 PA4 26 PB7 27 PB6 28 IC1 HT48R30A-1 L019SW DIP-28 LINK LK1 IS USED TO CONFIGURE PCB FOR USE IN P35 OR P1 FOR P35 - LEAVE LK1 INTACT FOR P1 - CUT LINK LK2 0R0 0W25 MF 0V_D KAL8/05/03Redrawn, LED

39、1, 2 swapped, Connectors rewired, LK1, 2 added1.003_E125 ITEM11Blank PCB P35/P1 FMJ Amp Microcontroller BoardL929PB TOOL1TOOL2 SPARE1 SPARE2 SPARE1 SPARE2 SPARE SPARE R25 10K 0W25 MF R26 10K 0W25 MF REDGRN LED3 3mm BICOL LED 3mm ISSUE DRAWING NO. DRAWING TITLE DATE Filename: ECO No.DESCRIPTION OF CH

40、ANGE L962CT1_2.0.Sch P1 Amplifier Main PCB Contact Engineer: L962CT1 22-Aug-2003 INITIALS Printed:11Sheetof Notes: Contact Tel:(01223) 203243Kevin Lamb A & R Cambridge Ltd. Pembroke Avenue Cambridge CB5 9PB Waterbeach 23425 VIPROT DC THERM SHUTDOWN* L962CT2_2 L962CT2_2.0_PSU and Control.Sch VIPROT D

41、C THERM SHUTDOWN* L962CT3_2 L962CT3_2 0_Power Amplifier.sch FD1 FD2 FIX2 Dia 3.2mm 1 FIX1 Dia 3.2mm 1 FIX4 Dia 3.5mm 1 FIX5 Dia 3.5mm FIX8 Dia 3.5mm FIX9 Dia 3.5mm FIX10 Dia 3.5mm FIX11 Dia 3.5mm FIX13 Dia 3.5mm FIX3 Dia 3.5mm FIX12 Dia 3.5mm FIX6 Dia 3.5mm 1 FIX7 Dia 3.5mm CHASSIS1 FD3 FD4 TOOL1 TO

42、OL2 TOOL3 TOOL4 FIX14 Dia 3.5mm CHASSIS1 CHASSIS2 QTYDESCRIPTIONPART No.NOTESITEM ITEM11Clip For SW Profile HeatsinkF006 ITEM21Fuseholder Cover For 20mm FuseholderF022 ITEM31Fuseholder Cover For 20mm FuseholderF022 ITEM41Fuseholder Cover For 20mm FuseholderF022 ITEM51Fuseholder Cover For 20mm Fuseho

43、lderF022 ITEM61Fuseholder Cover For 20mm FuseholderF022 Clip for REG1 Cover For FHLDR1 Cover For FHLDR2 Cover For FHLDR3 Cover For FHLDR4 Cover For FHLDR5 ITEM71Fuseholder Cover For 20mm FuseholderF022Cover For FHLDR6 ITEM81Blank PCB P1 Amplifier Main BoardL962PB ITEM92Pad Damping 15x6x3MM Sorbo han

44、eE802APSee Assy Drawing for location See Assy Drawing for locationITEM103Pad Damping 7 5x6x3 Sorbo haneE826AP ITEM111Earth Lead Assy 75MM8M101 03_E055KALMinor Change to re-label gain switch posi ionsA.118/02/03 03_E111KALB.011/04/03Corrected CON4, Redesigned protection cct and voicing mods 03_E184KA

45、LB.123/06/03Changed sorbothane part numbers, corrected R179-182, R185-187 03_E203KAL1 016/07/03Production Release, VI Limi ing changes 03_E249KAL2 022/08/03Stability mods ISSUE DRAWING NO. DRAWING TITLE DATE Filename: ECO No.DESCRIPTION OF CHANGE L962CT2 2.0 PSU and Control.Sch P1 Amplifier Main PCB

46、 Contact Engineer: L962CT1 22 Aug 2003 INITIALS Printed:23Sheetof Notes: Contact Tel:(01223) 203243Kevin Lamb A & R Cambridge Ltd. Pembroke Avenue Cambridge CB5 9PB Waterbeach 23425 EARTH EARTH MAINS WIRING AND AUXILIARY SUPPLY DGND +5V(D) EMC Shield SH1 L N E SKT1 BULGIN PX0580 C1 3N3 250V CER C2 3

47、N3 250V CER C5 220N 275V PP X2 LIVE NEUTRAL FHLDR2 20mm HLDR FHLDR1 20mm HLDR C4 3N3 250V CER C3 3N3 250V CER RLY1B Takamisawa F1CA005V RLY1A Takamisawa F1CA005V RLY1C Takamisawa F1CA005V DGND +5V(D) FS1T6.3AS506 FS2T6.3AS506 D3 BAS16 SOT-323 D7 BAS16 SOT-323 P7 C33 1000UF 10V YK 1A 1 1B 2A 2 2B 115

48、V230V SW1 18-000-0019 115V 115V 6 4 2 15 8 9V 9V 37 TX1 Open Frame 1 2 3 4 5 6 CON3 MOLEX 44472 GREEN 1 CON1 WAGO 256 TR7 FMMT497 SOT-23 R9 2K2 0W25 1206 R15 10K 0W25 1206 D6 BAS16 SOT-323 TR10 BC849B SOT-23 R16 2K2 0W25 1206 R17 4K7 0W25 1206 +5V(D) DGND C10 100N 50V 0805 L1 70R100MHz DZ1 BZX84C 4V

49、7 SOT-23 DGND C6 100P 100V 0805 R4 2K2 0W25 1206 P1 GND1 NC1 GND2 NC2 SKT2 HOSIDEN HSJ STANDBY* AC PRESENT TO DISPLAY CARD DGND +5V(D) C12 100N 50V 0805 C13 100N 50V 0805 C11 100N 50V 0805 P5 HS1A SW50-2 8.8C/W EMCGND CHASSIS1 MAINS PRESENT DETECT +12V(D) C9 100N 50V 0805 TR1 BD179 TO-126 TR2 FMMT497 SOT-23 R1 10R 0W25 1206 R3 3K3 0W25 1206 1 2 3 4 5 6 7 8 9 10 11 12 13 14 CON4 MOLEX 5229-NCPB AGND_C1 VP58V VN58V DBR5 GBU8D DBR6 GBU8D C24 10,000UF 71V AM C26 10,000UF 71V AM C25 10,000UF 71V AM C27 10,000UF 71V AM C22 1000UF 100V YK C23 1000UF 100V YK AGND_PSU2 D4 BAS16 SOT-323 VP7