[Bob Landry]

On Fri, 18 Sep 2009 15:55:53 GMT, (GregS) wrote:

In article , Bob Landry wrote:
On Fri, 18 Sep 2009 06:01:01 -0500, "Mark Zacharias"
wrote:

"Richard Crowley" wrote in message
...
"Bob Landry" wrote ...
Just deleted rec.audio.misc. since it seems to be populated by folks who
can't
seem to find *.*.politics. This groups seems to have folks who are
actually
interested in and knowledgeable about audio. I'm in the "interested"
group, but
not in the "knowledgeable" group.

I have a Dynaco SAT-4 that I bought used off eBay, along with a Carver
power
amp. I seem to have recently lost the right channel; moving the balance
knob all
the way to the right has no effect. I'm running the Carver into 2 Polk
speakers,
where I've used all 4 terminals on each, running two lines into each of
the 4
outputs on the Carver. I've checked and rechecked the connections, and
they're
all done the way the Polk instructions describe.

Is there any way to tell whether the problem is with the Dynaco or the
Carver
without taking it to a shop? The drop off occurs with the CD player and
the FM
tuner, also a Dynaco, so I think it's safe to say that the problem is
with the
electronics and not the speakers, right?

Any help for a new member and an electronic ignoramus greatly
appreciated.

The easiest way to identify whether the problem is in the preamp or
in the power amp is to simply switch right/left between them. If the
problem moves to the other side, then it is the preamp, if not, then
it is the power amp.

Do you have the technical info (schematic diagram, etc.) for either
equipment?



I'm going to assume this is a PAT-4, even though I'm not all that familiar
with Dynaco - I have worked on a couple PAT-5's and I know there was a -4
model...

Anyway, the PAT-5's suffered from a number of bad electrolytic capacitors on
various boards. This often resulted in missing or low channels. Perhaps the
PAT-4 had similar issues.

Obviously, controls etc should be cleaned as with any equipment this
vintage.


Mark Z.

Thanks for the answer, Mark. Yes, this is a PAT-4, and I'm seriously
considering
sending it off for a servicing and rebuild, although $250 for a $60 component
takes it out of the "bargain" class. Still, I bought it off ebay knowing (but
hoping not) that it would likely have issues.

As far as nuts and bolts are concerned, how does one go about cleaning
controls?
Do they have to be removed from the amp, or does one just pull off the knobs
and
spray away?

You usually never go in from the front, but sometimes thats necessary due to
restrictions.

Usual step, closly examine from the rear. Most items have openings.
The spray would go in there. After application, works the controls.

On your outside connections, RCA's etc, water is a good first choice
to help remove water soluable films and green oxide.. Also some cleaner like
Fantastic can be applied with a rag. On really bad items
I would try TarnX, or worst case Scotch Bright. Then lubricate with something like
Caig Fader Lube or Deoxit Gold, or CRC 2-26

For the controls you can use plain alcohol to get basic cleaning,
or most use Deoxit then work the controls. After that apply
Caig Fader Lube.

greg


Thanks, Greg. That was just what I was looking for. This group has been great
for information and patience with a rank electronic amateur!

Bob

Just your basic flake, and official Old Fart!
"The missing link between animals and the real human being is
most likely ourselves."
Konrad Lorenz