[Readily Visible]

Engineer wrote:
On May 28, 8:45 pm, Readily Visible wrote:
Readily Visible wrote:

(snip)

The left channel is playing now and no amount of poking this
specific tranny makes it drop out. When it does drop out, the trick of
turning the volume up to a specific point kicks it back in.

If it weren't for the fact that the left channel continues to be the one
to drop out after connecting the left preamp output with the right power
amp input and vice versa, I would bet money on the volume pot.


(snip)

It sounds like a speaker relay problem. I had an AM/FM receiver of
the same vintage that dropped one channel randomly (always the same
one) but it would sometimes come back if you "bumped" the volume up to
"too loud" and then back before the speakers/ears protested to much. I
had already changed the volume control - not a fix. At this point I
suspected the speaker relay contacts, i.e. higher speaker voltage
spike breaking down an intermittantly open relay contact. I
unsoldered the relay very carefully, removed the plastic case even
more carefully (these things are not designed to be user maintained!),
cleaned the contacts (fine abrasive paper plus switch cleaner) and put
it all back together. Problem solved, no more drop-outs.
Hope this helps.
Cheers,
Roger

Thanks, Roger, but I don't think the speaker relay is at fault. As I
posted earlier in this thread, when the left channel dropped out I
shorted the soldered terminals going into the speaker relay and got
nothing. I wish it were the speaker relay, but it definitely is not. I
bypassed it when the channel was out and got nothing.