[R-390] R 390A range of RF gain

[Craig]

Nelson,

Check out the Y2K, Chapter 5. Looking at my digital copy; figure 5-6 IF Sub-chassis, Voltage and Resistance Diagram......If your resistances & voltages are within in spec, chances are the pot in question is good to go. 

How R-103 controls might also be connected to the IF gain pot, other bugs in the radio. "I get nothing until I dial it up about 6 on the scale."; could be related to how strong the signal is.

Craig,

-----Original Message-----
From: R-390 [mailto:r-390-bounces at mailman.qth.net] On Behalf Of ngietz at mymts.net
Sent: Wednesday, March 11, 2015 8:59 AM
To: R390
Subject: [R-390] R 390A range of RF gain

    Still working on this 1963 Teledyne radio, and since it’s my first 390A, I’m not totally familiar with it.  So... how much of a control range should I expect on the RF gain control?  to 6 I get nothing until I dial it up about on scale.  the I tried subbing the original (I believe) with a nice Allen Bradley 5K pot and it seems to operate about the same.  Is this typical?
    The pot swings the cathode bias measured at the pot from 0V (max gain) to 
+21.5 (min gain).  Does that sound right?
   Nelson
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