Marantz PM62 Amplifier Repair

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Published
Fault
Amplifier powering up, speaker protection relay(s) changing over but no Audio output.

The PM62 is an absolute joy to work on, its modular construction and ease of access makes service and repair straight forward.

The input selection relays are controlled via the microprocessor which in turn reads the input status of the selection switch.

The 6 Volt supply for the Micro was checked on the output pin of Q802 NJM78M06FA Voltage regulator.

The voltage was low at 2.3 volts, input voltage checked correct at 24 Volts.

Q802 replaced fixing the loss of Audio issue.

Due to the age of the Amplifier additional work was carried out as detailed below.

Volume potentiometer replaced end travel stops broken.
Quad A50K Motorised.

Dry solder joints on the input RCA sockets re-flowed.
Broken off RCA plug pin removed.
Both Speaker protection relays replaced 24 DC Coil DP/CO 5 Amp rating.
Dry solder joints on the 3 rear power sockets reflowed and F092 T2.5 Amp fuse fitted.

Power Transformer relay 24 V DC DP/CO 5 Amp replaced.

Tone Board removed and dry solder joints reflowed and user controls and switches cleaned with De-Oxit to ensure noise free operation.

Bias for each channel set to 8.5 millivolts.

Amplifier fully tested working correctly.
Category
Audio
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