The BFO VCV is a very common issue, but not the only potential one. It will drift over time, and eventually reach a point where the VCV doesn't work at all and you get nothing on CW/SSB.? Switching LSB-USB without any change in the VCV frequency is interesting. I am wondering if you have an HMI.
Q: Can you receive or hear anything on AM or FM modes? If yes, the BFO is likely at least operational and we should look elsewhere.
Q: When was the last time you replaced the RAM backup batteries (behind the panel under the rig)? Have you done a RAM reset (pull out the batteries for at 2 minutes, replace with fresh batteries)? A lot of issues can be traced to this ...
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-Mat Breton, N8TW
Mat Breton N8TW