Last night I replaced the TIP36C bipolar transistor and reflowed the connection to the power plug with no improvement in the modulation or dimming of the display during SSB modulation.
I went rummaging through my radio parts stash and I do have a new L7808CV voltage regulator (U750), a new C2314 (Q109 pre-driver?) as well as six new IRF520 and four 13N10 MOSFETs (Q102, Q102, Q103, Q104). Is there any point in me replacing any of these (and checking/setting the bias) as a Hail-Mary type of play? I don't mind removing, testing and replacing these because the parts are inexpensive and I already have them. But if it's unlikely to help, I won't bother.
Beyond that, it's beyond my skillset and knowledge to even know what to do next. Then the decision would have to be to decide between the 6666 Pro, the QT60 Pro or Anytone Q5N2 short chassis. I like the larger display better on the latter two units but maybe it's because I'm used to my current Q5N2. The 6666 Pro looks like a great unit too!
You can also tell in the picture below that one of my daughter's cats has been closely supervising me whilst I poke around in the radio. He's very curious, and nosy.
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