[R-390] R390A AGC troubles

[Dennis Wade]

Hi Bill and all,

On 7/27/05, Bill Coleman  N2BC <n2bc at stny.rr.com> wrote:
> Hi Dennis, it was my understanding that zero input signal state is
> around -7V.
> 
      Once again I'm at work without a diagram, but if memory serves
me correctly, the -7 is at the Diode load terminals?  The zero signal
level might be differenta at the AGC jumper on the rear.  On my
Motorola, the jumper matches the IF amp grids.


> The other measurement that is 'wrong' is the suppressor grid voltage on V504
> & V508), it is +3.4V, should be -2.5V.
> 

         That DOES sound weird.  Have to look at the diagram.  My shop
has been running about 115 deg, so I've been out for a few days.  I'll
check mine when I can since I still have mine out on the bench.

            Dennis

> The voltage on the grids of the IF strip is consistent with the -0.5V.
> 
> Externally, it sounds like minor overloading on strong signals.
> 
> THX, Bill
> 
-- 
Dennis L. Wade
KG6ZI
Carmichael, CA