[R-390] R390A Popping

Sun, 28 Sep 2003 05:04:37 +0000

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]
> _______________________________________________
> R-390 mailing list
> [email protected]
> http://mailman.qth.net/mailman/listinfo/r-390