Jacques
Yes, this current RF Gain thread has to do with a low impedance on either the
AGC or common cathode lines, both affect stage gain. With the information
given, I am not sure what is the root of the problem. Don't recall any mention
of the position of the Function Switch or the position of the RF Gain control
pot. Is the R-390 at maximum or minimum gain?
If the overall receiver gain is still controlled by the RF Gain pot, no matter
the position of the Function Switch, then I would suspect that the 50uF cap is
good. IIRC this 50uF capacitor is an ancient style Tantalum cap which looks a
lot like Jeff Bezos' New Shepard rocket?
In any event, earlier threads (perhaps on another reflector?) concerned the RF
Gain pot itself and the various work-arounds to mimic the reverse log pot
function. I was just pointing out that a NOS part was available for those in
need.
Jim
Logic: Method used to arrive at the wrong conclusion, with confidence. Murphy
On Friday, November 14, 2025 at 03:34:07 PM CST, Jacques Fortin
<[email protected]> wrote:
Hi Jim,
They are from TEDSS again: I believe that is the only place were you can buy
the "real" replacement parts.
But the problem George have is due to the RF Gain line capacitor in his
R-390/URR (C231).
73, Jacques, VE2JFE in Montreal
-----Message d'origine-----
De : [email protected] <[email protected]> De la part
de Jim Whartenby via R-390
Envoyé : 14 novembre 2025 13:45
À : reflector R-390 <[email protected]>
Objet : [R-390] RF Gain pot
A bit pricy at $40 + $4 shipping but one is available on eBay, not my auction,
etc. Item # 134407933660
JimLogic: Method used to arrive at the wrong conclusion, with confidence.
Murphy ______________________________________________________________
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