[R-390] R-390A trouble

[David Wise]

Sounds to me like regeneration, frequently
caused by a bypass cap letting go or something
losing its ground.  That bad ground you fixed
might not be the only one.

Divide and conquer.  Got another IF deck?
Swap it in; that's where most of the gain is.

What do you gentlemen think?

73,
Dave Wise

> -----Original Message-----
> From: Jim Temple [mailto:jetemp@insightbb.com]
> 
> OK, I want to fix this receiver.  Here goes.
> 
> 1.  R-390A bought as a "massacre" yellow line from Fair Radio.
> 2.  After cleaning, and replacing many of the "problem" caps 
> (listed on many
> of the resident web sites), I corrected a below 8mhz problem, 
> by finding
> that the ground lug under T-207 was loose and insulated from 
> ground by a
> shellac layer.
> 3.  The unit, at first alignment, aligned well.
> 4.  At some point, within a couple of hours of operation, the receiver
> developed a screeching/motorboat putt putt sound.