"Mark D. Zacharias" wrote in message
news

Man.

This might be really easy. Q 405 conrols the turn-on delay. HK's don't use
relays, so they mute the signal til the amp stabilizes. On this model it
is Q405 and Q406 respectively. The transistor could be bad, but I would be
especially concerned with D401, R405, C405, C407, and D403, which is a 15
volt zener.

Could just be solder connections relating to the above, but in any case
you need to see that Q405 turns off hard a few seconds after turn-on.
The -12.5 or so volts at the base is critical.

Mark Z.
Something is still failing in my amp. As I noted, I put the original caps
(C401, 403, 405, 407) back in and the problem went away. For awhile. It's
back... I measured voltages after the right channel had cut out.

The collector of Q407 was 0V. So was the collector and base of Q409, and
the base of Q413. Makes sense as they're all tied together. The collector
of Q405 was also 0V. the collectors of Q411 and Q413 were ALSO 0V. I noted
that although R437 tested fine, it looks like it's been run hot. As in it's
dark brown and you can't really read the color bands any more.

I don't understand how Q405 works as far as the turn-on delay, but if it
were bad could it be causing no voltage where I've indicated?

I tested the other, working channel and all voltages were correct.

Thanks

Dave