Now, I know from reading some different posts that I'm unlikely to get much help over the internet for the range of specific problems these turntables have. But I'm going to share the symptoms first so that everyone can amuse themselves by imagining me, (a hobbyist with an excited look on my face and a new toy) sitting down to start logically troubleshooting one day, then feeling progressively more and more like a monkey trying to use a tin opener on a banana...
- When switched on, the stop button illuminates, the 33 and 45 buttons sometimes very dimly illuminate and the strobe flickers. Sometimes the 'down' led flashes erratically.
- If you press 33, lots of things flicker, the 'down' led pulsates erratically but slowly. Sometimes the table spins forwards at a non-specific speed which is not 33 rpm. All the buttons flicker like the strobe earlier or the stop button stays on. No buttons function anymore.
- If you press 45, the table often spins backwards, at a speed that might be about 45 rpm. But it's difficult to tell because it's a little erratic. The buttons are as above, but the 'down' led flashes erratically rather than pulsates. Nothing responds to input anymore.
So far, I've dusted out inside, checked for any obviously disconnected, dry or burnt things, and poked about with the optical lifting sensor to make sure it's in order. Seems to be visually so. I've also reviewed the service manual, which has not got anything helpful to say about crazy-robot mode.