"Michael A. Terrell" ) writes:
Michael Black wrote:

But the problem is we don't really know what he did.

He mentions those capacitors because he couldn't get the exact
value, but he said he recapped the receiver. That implies he
changed all the capacitors.

It would have helped if he'd said why he did the recapping. Because
there was an existing problem, and he hoped it would fix it? Because
he wanted to "improve the sound"? Because he figures they are old
enough that they ought to be replaced?

From what he's said, we don't really know if the problem is due
to the recapping, or existed before.


It is common practice for people who restore antique radios. Lots of
the paper insulated capacitors are leaky, so the shotgun that problem
before they damage tubes and other parts from improperly biased tubes.
The extra current can even fry an old power transformer. That was why I
recommended the news:rec.antiques.radio+phono newsgroup. Its an
excellent source of parts and information for this old radios. There
are also people there that make reproductions of hard to find parts and
knobs.

I'm not arguing against the practice, just pointing out that why
someone does it might help define where the problem lies.

If there was an existing problem, the capacitors just might not
have been the problem.

If there was no problem, but now there is, then it's indicative of some
issue related to the replaced capacitors (though obviously it can always be
some coincidence that something else failed at this moment).

It's not going to be due to those .068uF capacitors because their
value is different, but obviously it could be a bad electrolytic replacement,
or perhaps a reversed electrolytic. It might be a coupling capacitor
that turns out bad. It could be that in the spaghetti the poster overlooked
a capacitor that ends up being the problem.

It's obviously easy to shotgun replace parts when something fails, but
if that doesn't solve the problem, nothing's been done to figure out
where the problem lies. As it now stands, the capacitors have been
changed and there is still a problem.

Michael