bayard1music
Member
Hello,
One of my 1996 vintage mono block amplifiers decided to stop working on Friday night. It starts a bit garbled and turns off the audio within a second or two. The amplifier is still powered, and have tried an alternative speaker/cable arrangement. I'm technical (electronics background) but not that conversant repairing audio gear. Lack of work forces the most economic repair. I've taken off the lid and can confirm:
i) The two DC 60V rails are still present and working following the immediate sound reduction (to zero)
ii) At a reasonable glance no signs of a burnt out or leaking component (component side view only).
iii) I can see a legend marked s.c. (short circuit) protection and guess this has fired to protect the speaker connected. Hence the muted sound.
I've looked around on line and can't see a schematic so tricky (for me) to debug.
Wild guess's at present include a faulty output transistor dragging the output down ? Has anybody got any specific experience or advice that they could offer. A schematic diagram would be good ! Image attached of the board.
I do have another working example and plan to take some measurements and compare the two if all else fails.
One of my 1996 vintage mono block amplifiers decided to stop working on Friday night. It starts a bit garbled and turns off the audio within a second or two. The amplifier is still powered, and have tried an alternative speaker/cable arrangement. I'm technical (electronics background) but not that conversant repairing audio gear. Lack of work forces the most economic repair. I've taken off the lid and can confirm:
i) The two DC 60V rails are still present and working following the immediate sound reduction (to zero)
ii) At a reasonable glance no signs of a burnt out or leaking component (component side view only).
iii) I can see a legend marked s.c. (short circuit) protection and guess this has fired to protect the speaker connected. Hence the muted sound.
I've looked around on line and can't see a schematic so tricky (for me) to debug.
Wild guess's at present include a faulty output transistor dragging the output down ? Has anybody got any specific experience or advice that they could offer. A schematic diagram would be good ! Image attached of the board.
I do have another working example and plan to take some measurements and compare the two if all else fails.
