I am glad that you found the problem. That FRG-7 is a nice receiver. Nothing
like home radio repairs. I repaired a Grundig Satellit 3400 for a friend of
mine, so he gave me a Yaesu FT-211. The memory battery was bad, so it
"dumbed down" the microprocessor. I removed the battery and reset the uP,
and everything is working ok.
He has another Satellit 3400 for me to repair. The BFO injection frequency
has drifted out of the I.F. passband, so it will be a simple adjustment to
recalibrate that. The big thing is the turret bandswitch......the designer
uses a square shaped nylon bushing that has a round hole in its center. This
bushing keeps the turret in position, so that it makes good mechanical
contact with the finger stock contacts, similar to the bandswitch in a
Hammarlund SP-600. My unit had the same problem. Since only 1mm or so is
required to shim the bandswitch, copper tape works fine. This eliminates the
front to back play that can develop over the years.
His other 3400 had the typical problem of the blown RF amplifier for the
single conversion ranges. Since the original transistor doesn't seem to be
available, an MPS-H81 (also a PNP device) is a great substitute. This device
has a higher Ft than the original, so the sensitivity is actually improved
over a stock 3400. Of course, you see the usual problems, such as an
oxidized I.F. bandwidth switch, etc. I thing that the Satellit 3400 was
probably the best design they ever made, even better than the Satellit 6001.
I also have one of those units. Too bad Grundig got away from that turret
bandswitch, with its gold plated contacts.............that design was a
classic.

Pete