Hi John
If you’ve made the uPC TEST with in STBY Mode pressing MONITOR and STBY Button simultaniously and the display shows “TP” that means Test Passed so the uPC is in working order.
If there is any error detected during the TEST the display would show TE (Test Error) 1 to 13 depending of the detected error.
Is there any noise in the speakers like humming or white noise if you crank up the volume?
If not I would do following:
Often the speakerswitches are corroded or not working properly.
Check if they are switched to the “ON” position ;-))
Maybe toggling the switches bring them back to life.
Connect a audiosource to “TAPE IN 1 or 2”, key TP1 or TP2, try both, there are different ways through the audio switches IC’s
Check the Amp with a headphone conected.
The headphonejack is connected to the poweramp section with a voltage divider and no switch is between.
Let us know your results.
Kind regards
Christian