Op Mon, 20 Nov 2006 22:02:55 +0000, schreef Ken Weitzel:

Richard Rasker wrote:
Hi all,

I'm trying to fix an old Heath amp, the AA-1600.

[snip end stage keeps blowing up]

A somewhat low-quality schematic diagram can be found he

http://web.archive.org/web/200106071...th/aa-1600.gif

Does anyone have an idea what might be the problem? Or how I could trace
down the problem without blowing yet another set of end stage transistors?
I'm particularly puzzled by the fact that the wretched thing only blows up
when loaded and at the same time connected to the 'hard' mains voltage
(230V AC). Even with a low-ohm load in series, the amp behaves just fine ...

Hi Richard...

Happens that I still have the whole manual for the aa-1640, but no
idea at all how much it differs from the 1600. I'm also on the
other side of the puddle (Canada), though I doubt that would make
much difference other than to the power transformer.

If you think it might be similar enough to help, I'll be happy to
scan a few pages for you.

Thank you for the kind offer, but I found someone here willing to copy &
send me the complete manual - although he said that it probably won't give
more clues as to what goes wrong. Also, I'm quite experienced in these
matters myself (I very rarely have to give up on something like this), and
the schematic is simple enough. I just hoped that someone here would
recognize these symptoms and tell me the "golden clue"; from searching the
Internet I already found that the AA-1600 almost never breaks in any
serious way, so that wasn't succesful either.

Thanks again all the same, regards,

Richard Rasker

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