These groups need a "Belay that..." button due to what happened next.
As soon as I hit "send" on my previous message I went to check on the rig, and the misbehavior which prompted me to replace TC01 was back. Hmmmph. Since I had a production line set up at my rework area I changed the trimmer on every loose PLL/VCO Unit I had and tried each in the rig - along with one from another radio in the repair queue. Apparently, the issue wasn't with that assembly - sounds like random noise modulating the VCO and eventually it drifts out of lock.
I swapped a spare BFO Unit in and that cured it. Question for Matt/Wald and whomever else has repaired this assembly: When the RF transformer went bad (open), what were the symptoms? I think this may be what's going on here.
A second rig in the queue appeared as deaf as a post. Its RF Unit was swapped into a working rig for test purposes and is fine. Next, the IF Unit was swapped...problem follows the board. That one's now headed into my "test mule" for additional troubleshooting. I've a couple things to do WRT RF Unit testing (evaluating a spare board) and installing filters but two of the rigs are coming along nicely.
Wants:
If anyone has a spare Inrad 2110.1 (2.4KHz B/W; 8.9875MHz center) filter or its Fox Tango/Seiwa equivalent, I'm interested in buying it.
Will post more as I solder.
73 - Fred, N8YX
