[R-390] R390A AGC troubles

Dennis Wade sacramento.cyclist at gmail.com
Wed Jul 27 18:11:42 EDT 2005


I'm at work, but I don't recall that -0.5V zero signal on the AGC bus
was a problem.  When I finally got mine fixed (different problem
though, see previous posts) the small + zero signal voltage I had been
seeing became -0.4V.

What are the grids of V%01, 502 and 503 doing?  What do you "hear" in
terms of symtoms..how does the radio sound under various signal
conditions?

Dennis

On 7/26/05, Llgpt at aol.com <Llgpt at aol.com> wrote:
> 
> It is quite possible the "cadaver" Z-503 is a bad one too. They are a known
> troublesome part. If possible try a known good if deck. Maybe you have a
> friend  close by.
> 
> Les Locklear
> 
> 
> In a message dated 7/26/2005 2:47:01 PM Central Daylight Time,
> n2bc at stny.rr.com writes:
> 
> Along  the way I managed to destroy Z503 so I pulled one out of a 'cadaver'
> IF  strip.  I noted that it's slug is fairly well centered in the core.
> Upon
> replacing Z503, the 'new' one behaved the same way.... increasing  stage
> output as the slug was cranked toward the top but it runs out of  adjustment
> before peaking.
> 
> 
> 
> 
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-- 
Dennis L. Wade
KG6ZI
Carmichael, CA


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