Arcam P75 Plus service manual A65, A75 & P75 Service Guide

Page 4

A65, A75 & P75 Service Guide

Fault diagnostics

 

Fault

Action

 

No power

Check mains fuse

 

 

Check transformer connections

 

 

Check power supply rails

 

Stuck in protection

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 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 terminal

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, 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 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.

Image 4
Contents DiVA A65, A75 & P75 Plus Amplifiers Contents List A65/75/75P Plus Circuit Description A65, A75 & P75 Service Guide USE exlude A65 Filter for BOM L942C1Left Channel Power Amplifier IR RX Support PAD SP1 Motor Driver Volume Drive L942C7Phono Stage & Input Selection L942C2 ScreenRight Channel Power Amplifier Pre-amp Out, Tone & Headphone A75 Plus AMP L940C1Left Channel Power Amplifier L940C5L940C7 A75 Amplifier Plus L940C3L940C2 LK1 LK6L940C6 L940C4 0VSIG L809CADisplay PCB for A75 AMP Page Page A65/75 Display Board L8851.1 Arcam Thermistor Siemens B59008 Jumper 2 W Lead APL5 VOLMOT900 220NF Class X2 CAP 275VRMS CS1 Trans LF SS N BC546B Jumper 8-WAY Lead Alpha 8 AMP Multi Voltage Transformer Thermistor Siemens B59008 LK149 LK150 LK151 C606 C626 C706 C709 SW Push 4PCO LK168 A75 Heatsink Clamp LK151 LK152 LK153 WAY DIL PIN Header A65 Plus General Assembly HL4SA M4 Shake Proof RR PAN ‘E HL4SB A75 Plus General Assembly HJ4COOD Brass NUT Earth HL4SA M4 Shake Proof HL4SB P75 Plus General Assembly
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