[R-390] R390A Blowing fuses...newby question

[Larry H]

Hi Dave,  This doesn't sound good.  I assume that when you said you
unplugged all the connectors except the power supply, you did unplug both
of the connectors on the audio module.  Just to verify, is this a 390A
unit?  If so, it sounds like there is a wiring problem with the B+ line.
With power off, you could measure it from the plug you disconnected from
the audio module.  Also, is this a single fuse unit?

Regards, Larry

On Sun, Mar 29, 2020 at 1:09 PM R. David Eagle via R-390 <
r-390 at mailman.qth.net> wrote:

> I have been working through the alignment procedures outlined in my manual
> and am now on day 3 of it.  Everything was going great with the alignment
> yesterday and receiver was on WWV and sounded great.  I came in this
> morning and flipped the switch on to warm it up, and poof the fuse blew.  I
> was extremely blown away because it was working fine when I shut it down
> for the evening.
> So I went through and pulled all of the plugs off the modules except main
> power supply plug.  I put a new fuse in and poof...it blew again.  I pulled
> the rectifiers which are actually the soft start upgrades from sigmapert,
> put a new fuse in and everything seemed ok as the transformer powered.  I
> then became suspicious that that the soft starts went bad and I plugged one
> of them in  and it powers up fine with it in either socket.  Here is the
> weird part - I did the same to the other one and it works fine as well, BUT
> if  I have both plugged in it blows the fuse.
> So I then pulled out the original 26Z5W's and plugged them in and all is
> good until one of them warms up and the fuse blows.  I then verified the
> wiring on the drawing and traced one wire that comes from the rectifiers to
> CR102 and unsoldered that and still get the same results.
> Another odd thing that has transpired is that when the radio is switched
> to the off position, the frequency lights are on....???
> Has murphy decided to come play for the weekend or has my radio been
> plagued by the Corona?
> Thanks again,
> Dave
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