[William Sommerwerck]

"Readily Visible" wrote in message
...

I am deaf in one ear and cannot locate the direction
from which a sound originates...

Why am I reminded of André De Toth, the director of "House of Wax", who was
blind in one eye?


diagnostic material snipped

Long story short, the dead channel at the speaker jacks switched from
left to right when I switched the preamp outputs going to the power amp
inputs.
I have to put this aside for a minute and re-read all the relies I have
gotten dealing with possible cause on the preamp side of the unit.
My apologies to all who followed me down the wrong path with this unit.
Time to start fresh... mañana.


ARRRGGGHHH!

Lemme tell you a story...

Way back in 1980, when I was living in PA, an acquaintance asked me to help
a friend diagnose a problem with his Dayton-Wright preamp. I don't remember
what the problem was, but there _was_ an obvious likely cause.

"Did you check thus-and-such?"
"Yes."
"You're absolutely certain?"
"Yes."
"You're really, really sure?"
"Yes."
"Okay, bring it over and we'll have a look."

I hooked the preamp to my Lux Laboratory Reference Series components, and
when I moved the input selector switch, both output stages of the power amp
were blown out. "****ed" is hardly the adjective.

Naturally, I sent the guy packing -- and the power amp to Lux for repair.
(That's called "zeugma" -- one verb yoked to two subjects.) I later learned
that he had not properly checked out the unit, and that my original
suspicion as to the nature of the problem was correct.

There are several points to be made. One is that it's not a good idea to
help people who you don't know, especially when you're not being paid for
it. Another is that you should thoroughly check someone else's equipment
before you put it in your system. * (DC offsets and output oscillations are
good things to look for.)

But the most-important point is that you can't trust other people to
correctly describe what's wrong with their equipment. Heck, you can't even
trust yourself! How many times have you gotten thoroughly confused as you
work your way through the diagnosis?

Nevertheless, I hope Readily Visible's SX-838 bursts into flames while he's
asleep, burning his house to the ground and destroying all his possessions.
And his little dog, too.

* In this case, I wouldn't have caught the problem. It turned out that the
Dayton-Wright preamp used switches that were very good at generating RF when
opened or closed. The RF caused the triple-diffused output devices in the
Lux 5M50 to melt from tertiary breakdown, a known problem with this power
amp. (Ironically, Mike Wright was aware of the RF problem with the preamp,
and had added holes to the PC board for suppression caps. Unfortunately, the
holes were not populated.) This was not the first nor the last time this
happened; the next time was my own stupid fault.