Arcam-DivaA65-int-sm维修电路原理图.pdf
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1、A65/75DiVA A65, A75 & P75 PlusAmplifi ers Service Manual ARCAMARCAMIssue 1.0RadioFans.CN 收音机爱 好者资料库 Contents List ! Contents list ! Circuit description ! Service guide ! Circuit diagrams ! Component overlays ! Circuit board parts list ! General assembly parts list RadioFans.CN 收音机爱 好者资料库A65/75/75P P
2、lus Circuit Description PSU In order get the output devices to turn fully on and achieve the greatest efficiency, an auxiliary rail is formed from a charge pump driven by the main AC outputs from the transformer. C304,305 & D301,302 charge on alternate cycles. In the other cycle the charge on C304,3
3、05 is pumped into C310,311 respectively. This creates a voltage much greater than the standard rails, but with low regulation and high ripple. This is then regulated to 38V via emitter followers Q300,302,303,305 from a zener stabilized voltage (D304,305) The Pre-amp 15V supply comes from linear regu
4、lators Z300,301. The transformer is a dual voltage unit, the required voltage being selected by which fuse holder is fitted with the appropriate fuse. If an alternative to 115V or 230V is required then a different transformer is fitted. The secondary is centre tapped for the main rails, but a separa
5、te winding is added for the uC supply. The star ground point SP300 is not a component on the PCB and is on the schematic only for layout purposes. Pre-amp The direct signal path (line in, tone controls defeated) consists of a single op-amp gain stage, buffering the j-fet input multiplexers and Tape
6、Monitor and AV switches. The selected input is AC coupled to the op-amp, the output is DC to the Pre-out, via a j-fet pre-mute switch. This switch is controlled by the uC in such a way that when ever the output relay changes state signal is removed from the power amplifier (A65/75). The MM phono sta
7、ge (by passable A75 only, SW100) is opamp based. The circuit is AC coupled to give RIAA/IEC low frequency response. The cartridge is loaded by R100,101,C119,120. The 1kHz gain is 56dB, and RIAA eq set by R110,112,111,113,C127,129,128,130. Each line input has static protection afforded by the back to
8、 back diodes (e.g. D101,103), and RF filtering is set by R118,C134 etc. The selected input is buffered for Tape output by Z104 set as a follower. The output resistor is inside the feedback loop so to keep the output impedance low and short protection is catered for. C121,122 maintain stability into
9、capacitive loads. From the tape monitor switch (Z105) onwards the signal is AC coupled (C151,152). From there the signal is fed to the tone controls. These consist of two stages: Balance and buffer (Z160), and Bass/Treble Z161. The output of this stage is again AC coupled. Switch SW162 selects wheth
10、er the tone adjusted signal or a direct signal reaches the gain section. In the A75 Z164 can be used to bypass the volume control when AV input is selected. This fixes the gain to allow an external AV processor to control the volume setting. The gain stage (Z163) has a gain of 2.2, and the same low
11、impedance output arrangement as the Tape output. The signal from this stage to the Pre- amp outputs and the Power amp input is controlled by a A65, A75 & P75 Service Guide Fault diagnostics Fault Action No power Check mains fuse Check transformer connections Check power supply rails Stuck in protect
12、ion Check power supply rails Check protection circuit voltages Check for dry joints on o/p devices Intermittent audio on one channel Check for dry joints around o/p devices Fails to respond to commands Check supply to remote circuit Check IC Z900 Check remote flex foil cable Check for dry joints on
13、selector pcb Volume control rubs on front panel Pull knob out from fascia Audio crackles on o/p Check for component break down using hot air gun & freezer spray Check transformer connections Power supply test points Position Voltage LK125 +37 volts DC LK126 -37 volts DC LK271 or black speaker termin
14、al 0 volts LK303 +15 volts DC LK301 - 15 volts DC Q300 emitter +38 volts DC Q304 emitter +38 volts DC Q302 emitter -38 volts DC Q305 emitter -38 volts DC D910 emitter +5 volts DC remote supply IQ settings Model IQ setting Comments - (22/01/02) A65 37mV A75 37mV P75 37mV A85 12mV Set for 8.5mV cold,
15、reset for 12mV when warm P85 12mV Set for 8.5mV cold, reset for 12mV when warm A65 plus 12 to 15mV A75 plus 12 to 15mV P75 plus 12 to 15mV Hints & tips ! To isolate a fault between pre and power stage remove C602 (left channel) or C702 (right channel). ! Always check and re-solder o/p device SAP15N
16、and SAP15P pin connections. ! Replace Z900 IC if software version is below version 3 ( note version 82 is also ok ). ! Make sure R127 is not touching LK130. ! When replacing the top cover with a new top it may be necessary to re-drill the fixing holes. ISSUEDRAWING NO.DRAWING TITLEDATEFilename:ECO N
17、o.DESCRIPTION OF CHANGEL942C1_1.0.PRJA65 PLUS AMPContact Engineer:L942C111-Dec-2001INITIALSPrinted:17SheetofNotes:Contact Tel:(01223) 203 200Travis PierceA & R Cambridge Ltd.Pembroke AvenueCambridge CB5 9PBWaterbeachPWRLEFTPROTECTIONA1SP2_SEND_LSP2_RETN_LOP_LA1LEFT CHANNELL942C5_1.0.SCHACLT1MUTEAVCO
18、NTROLTAPECONTROLMUX1MUX2MUX3PREMUTEPROT SENSEREMOTE CONTROLL942C7_1.0.SCHSELOPRSELOPLMUX1MUX2MUX3TAPECONTROLACSENSEPROT_OP_LPROT_OP_RPROTECTIONMUTEHPSW2HPSW1TAPOLTAPORPROT SENSEPHONO & INPUTSL942C3_1.0.SCHACSENSEACLT1POWER SUPPLYL942C2_1.0.SCHPWRRIGHTA1SP2_RETN_ROP_RSP2_SEND_RA1RIGHT CHANNELL942C6_1
19、.0.SCHPWRLEFTPWRRIGHTSELOPRSELOPLHPSW2AVCONTROLHPSW1SP2_SEND_LSP2_RETN_LOP_LOP_RSP2_SEND_RSP2_RETN_RPREMUTETAPORTAPOLPROT_OP_RPROT_OP_LTONE CONTROLL942C4_1.0.SCHTGP12/12/01PRODUCTION RELEASE1.0USE exlude A65 FILTER FOR BOM01_E020TOP SHEET FOR A65 L942AYISSUEDRAWING NO.DRAWING TITLEDATEFilename:ECO N
20、o.DESCRIPTION OF CHANGEL942C5_1.0.SCHA65 PLUS AMPContact Engineer:L942C511-Dec-2001INITIALSPrinted:57SheetofNotes:Contact Tel:(01223) 203 200Travis PierceA & R Cambridge Ltd.Pembroke AvenueCambridge CB5 9PBWaterbeachQ600BC556BQ601BC556BQ6042SA970GRQ606BC546BQ607BC546BR617680R MFR61910K MFR61810K MFR
21、61347R MFR61447R MFR612100K MFR6001K0 MFPWRLEFTQ6112SC2240GRQ6102SC2240GRR62010K MFQ6032SA970GRQ608BC546BQ609BC546B+C601100U EL 100V+C600100U EL 100V0V_HF+C61610U ELL6002U2H LAC SMALLR6312R2 CFR6304R7 W2 CFD6031N4003F+37V-37VC621470P CDRLY1ARLY G5Z-2A-EC620470P CDC6221N0 CDSPLD600SPLS600PD6OP_LSP2_S
22、END_LSP2_RETN_LR6162K7 MFR611100K MFC603100P PPW0V_SIG0V_HF0V_SIG0V_HFQ6122SC2240GRR627430R MFR606100R MFR605100R MFR6256K8 MFR62210K MFR621680R MFR62947K MF+C61710U ELQ605BC556BA1PROTECTIOND6041N4003FR628430R MFR6266K8 MF+C61810U ELR608100R MFR607100R MFA1D6051N4148D6061N41480V_LS_L0V_LS_LQ602BC556
23、BR61547R MFR601100R MFR602100R MFR603100R MFR604100R MFSPLE600Left Channel Power AmplifierQ614SAP15NQ615SAP15PD6004V7 400MWISSUEDRAWING NO.DRAWING TITLEDATEFilename:ECO No.DESCRIPTION OF CHANGEL942C7_1.0.SCHA65 PLUS AMPContact Engineer:L942C711-Dec-2001INITIALSPrinted:77SheetofNotes:Contact Tel:(012
24、23) 203 200Travis PierceA & R Cambridge Ltd.Pembroke AvenueCambridge CB5 9PBWaterbeachWARNING SAFETY CRITICAL COMPONENTREPLACE WITH IDENTICAL PARTuC, Volume Drive & Remote ControlC91210N CDC90010N CDR9001R0 FUD9061N4003FD9071N4003F+C9201M0 25VC91310N CDMOTE900P900+5vVOLUME DRIVEMOTOR DRIVER+5VGND1MD
25、12CC13REF4MC15MC26VCC17VCC28CC29MD210Z905BA610912VOLMOT9001Y271ACLT1MUTEMUX1MUX2MUX3AVCONTROLTAPECONTROLR915220R MFA01A12A23VSS4SDA5SCL6WP7VDD8Z90624C01C917100N CDX900CST4.00C918100N CD+C914220U EL+5v+5v+5vC919100N CD123SW900A2PCO_NON_LAT456SW900B2PCO_NON_LATR912100K MF+C92110U ELD9101N4148R91310K M
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