[R-390] R390A BFO /100kc calibrator not working

[Craig]

Chuck,

Hi 5's on the Motorola, good components were used and will be a fine
receiver. First, let's find out what you have there? Start with the BFO, is
the ballast tube there & is it working? With a ballast tube, the BFO & PTO
tubes should be 6BA6's. 

No ballast tube, pins 2 & 7 should be jumpered on the ballast tube socket.
12BA6's are used in this configuration. 

Got a 12BY7 in the ballast tube socket, the socket has to be rewired under
the IF deck. I think 6BA6's are used in this configuration. 

At this time, there is no manual in front of me or skizmatic. On the back of
the receiver there is a hole so that one can insert a screwdriver and adjust
the trimmer cap for the BFO. Give it a twist or two; any change. Does the
BFO oscillate anywhere while rotating the trimmer cap.

I had the same issue with my famous "Too Loud Amelco". Using a small freq
counter, MFJ-888, I put the telescoping antenna next to the two tubes used
for the BFO circuit. Darned thing was oscillating at 151KC; not at the
required 200KC. 

Then with the help of tube extenders (RF deck is no joy to remove and test
live) voltages were checked, no joy. Not wanting to spend a life time
removing and replacing the RF deck, all of the silver mica caps were
replaced. That fixed it.

Also don't forget the 200KC crystal. They ain't cheap, don't drop them. If
you have another from a working R-390A give it a go first.

Let us know how things are moving along.

Happy Thanksgiving & a Merry Christmas,

Craig

  

-----Original Message-----
From: R-390 [mailto:r-390-bounces at mailman.qth.net] On Behalf Of Chuck Claus
Sent: Tuesday, November 24, 2015 6:17 AM
To: r-390 at mailman.qth.net
Subject: [R-390] R390A BFO /100kc calibrator not working

recently purchased Motorola R390A at local ham fest replaced most of tubes
AM mode receive fine but BFO and 100kc calibration does not work


any help greatly appreciated


Thanks


Chuck




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