[R-390] R390A Popping

5 Oct 2003 14:21:31 -0000

I may have been the "other" person on the list, as I had this same problem 
and have shared it with some.  The problem was in the small coax cable that 
goes connects the limiter to the diode load.  It was very tough to 
troubleshoot, and finding it was mostly a process of elimination.  I was 
able to unsolder the coax at both ends, and test with a piece of coax 
jumper prior to removing the old coax and relacing it back into the wiring 
harness.

Good luck,
Walter - KK4DF
http://www.r-390a.us

On Sun, 28 Sep 2003 05:04:37 +0000, [email protected] wrote :

> I had the same problem.  Unfortunately it turned out to be a break down 
in 
> the center insulation of the mini-coax cables carrying the diode load 
signal 
> from the IF module, to the rear terminal strips, up to the front panel, 
etc.  
> After tediously replacing these coaxes the problem went away.  I was put 
onto 
> this by another on the list several years ago who had experienced the 
same 
> thing.  I forget who.  Popping will tend to be more noticable when the 
diode 
> load voltages go higher due to the breakdown in the coaxes.   Strange but 
> true.  Of course it could be otherthings too, like bad caps, a bad tube, 
> etc.  Good luck.
> > Guys,
> > My R390A has recently developed a problem. 
> > During ordinary listening conditions in either AM or SSB, it pops at
> > regular intervals. The signal strength meter jumps when this occurs.
> > But, the pops are not always the same amplitude on the meter. The
> > popping seems to respond to a change in agc settings.
> > At first I thought it was external interference as it quits when the
> > antenna was disconnected. However, after comparing other receivers in
> > the shack and hearing nothing, I came to the conclusion it is internal.
> > Before tearing into the radio I thought I would ask the group for ideas
> > and suggestions
> > TIA
> > Chuck
> > [email protected]
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