Technics SU X101 Amplifier Repair

Amplifier appeared not to be powering on, no display indication.

DC power supply voltages checked, plus 14.6V and minus 14.4V missing.
Voltages checked on the collectors of the two series regulator transistors
Q703 and Q704 plus 42.7V and minus 41.3 V present.

R701 4K7 ohm and R702 5K6 ohm checked both found to be open circuit.
Hence Q703 and Q704 were not being turned on.

Resistors replaced fixing the issue.

The video shows the usual dry solder joints on the main Amplifier board, Head Phones socket board.
All reflowed to avoid any future issues.

Display / Tone board removed and the user controls cleaned with De-Oxit to ensure noise free operation.

The display and viewing window was also cleaned as dust build up over time reducing brightness and clarity.

Amplifier reassembled and DC offset checked across each speaker terminal(s) low at a few millivolts.
The SU-X101 does not incorporate a speaker protection system hence there is no relay.

Amplifier fully tested working correctly.
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