21-05-2013, 06:23 PM
For some reason my reply to Alan Beckett's post #13 doesn't appear!. In the A500 which I'm (carefully)checking, there is no connection to the 'Chassis Ground' side of R267/C210, nor ever has been.
The speaker common negatives are connected to the '0V' line, whilst the mains transformer's secondary winding is connected to the 'Gnd' side of R267/C210. In other words there is no connection between the center tap and the '0V' line. Maybe this caused the transformer to fail? I have now added a ground wire, and will fit a replacement transformer after further tests. None of the components test faulty, or appear stressed or burnt, though!
The speaker common negatives are connected to the '0V' line, whilst the mains transformer's secondary winding is connected to the 'Gnd' side of R267/C210. In other words there is no connection between the center tap and the '0V' line. Maybe this caused the transformer to fail? I have now added a ground wire, and will fit a replacement transformer after further tests. None of the components test faulty, or appear stressed or burnt, though!
