Teac A R650MK2 Amplifier Repair (With Audio Tutorial)

Fault 1
Amplifier in protection mode, Power LED flashing red.

Failure of the left channel.
Following components replaced.

Sanken Output Transistors
Q518 - 2SC3519A & Q520 – 2SA1386A
Resistors
R535 680 Ohm 1 W
R536 470 Ohm 1 W
R532 / R533 100 Ohm ¼ W
R533 / R538 Ohm ¼ W

Bias for each channel set to 5 millivolts.

Fault 2
Power switch sticking.
Metal mounting plate removed and re-aligned.

Fault 3
Intermittent loss of sound left channel.
Volume control / pre-amplifier board connecting pins cleaned with a fibre glass pencil.
Socket on the Tone Board cleaned with De-Oxit.

Amplifier fully tested working correctly.

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