[R-390] Z-503

[David Wise]

I don't recall you saying you've replaced C551.  If you did and I missed it, sorry.  If you haven't, do so!  Every C551 in every R-390(*) is leaky.  A quick check is, does your symptom only show up when AGC is SLOW or MED, and it's okay on FAST?  If so, then C551 definitely.  It's a big can on the IF deck.  It's a pain in the neck to empty out; unless you're a purist, abandon it in place and install a new cap nearby.  They are much smaller nowadays.

You might consider applying one of the Moment of Silence mods at this time, since both Charles' and my recipe locate the new caps on the front panel instead of the IF deck.  Save you effort refitting the deck and then maybe abandoning that work later.

HTH,
Dave Wise
SWL in Hillsboro Oregon
________________________________________
From: r-390-bounces at mailman.qth.net <r-390-bounces at mailman.qth.net> on behalf of Charles Steinmetz <csteinmetz at yandex.com>
Sent: Sunday, February 16, 2020 9:33 AM
To: r-390 at mailman.qth.net
Subject: Re: [R-390] Z-503

Ross wrote:

> Hi Charles, The frustrating thing about the AGC problem is that  it seems OK when the radio is cold for a few minutes to a few hours then fails on strong stations. I used 2 cans of freeze spray  and couldn't isolate  the problem.  I am suspecting  that I may have an alignment issue.

OK, so you didn't say the problem was warmup-related.

What, in the symptoms you are seeing, suggests to you that it might be
an alignment issue??  Alignment does not change much as the radio warms
up (unless there is a temperature-sensitive component that mistunes
something -- but then it isn't really an *alignment* problem, in that
realigning the radio won't fix it -- it's a failed component problem).

> I must have missed your troubleshooting post   *  *  *  How do I find the post??

At the bottom of every list message are several links.  One is a link to
the R390 list home page.  If you follow that link, you will find (among
other things) a link to the list archives.  Go to the archive, open the
archive for the month when I posted it, and then find the date and you
will see the message.

Best regards,

Charles