[R-390] Fwd: Z503 Replacement

[bavarianradio at comcast.net]

----- Forwarded Message -----
From: bavarianradio at comcast.net
To: "Don Heywood" <wc4g at knology.net>
Sent: Thursday, April 7, 2011 4:31:36 PM
Subject: Re: [R-390] Z503 Replacement

Hi Don,& the group, Replacing the 3 micas in the limiter circuit took care of the distortion. THANKS!!! By the way, this problem started out as a heat problem. The radio worked OK till it warmed up,then the distortion would creep up. Eventually the problem was there all the time.  Now it's OK and the AGC is OK too!! 
 I guess the Z-503 question is somewhat answered, at least we know that the 390A coils will work on the 390. I surmize that the opposite may be true as well. At least we know that the radio doesn't burst into flames while trying....
 I think that a  replacement would be a popular item here if someone were to come up with a "cheap and dirty"  option to cannibalizing all the 390A's for their Z-503's. I now have a working(albeit temporarily) 390 Z-503 to rebuild or just examine. 
 Thanks to all who posted, Ross W1EKG
----- "Don Heywood" <wc4g at knology.net> wrote:

Distortion with the LIMITER off is a common problem in the R-390/URR,
the
fix is to change out a couple of mica caps in the limiter circuit. I
think
the "A" version is similar. I'll bet that if you change the mica caps
like
you are going to do, you will be good-to-go.
73
Don WC4G
Charleston, SC