I'm having the same problem with my G90. With the "blue" USB dongle plugged in for freq. control, the radio head unit won't drop out of transmit when it's removed. If I activate the antenna tuner, it will drop out of transmit. (Note: the "body" of the radio drops out of transmit but, the head unit does not until I activte the tuner)
I have adjusted audio levels by lowering and/or raising with some intitial sucess via testing/tuning but, when sending a beacon or CQ, it always comes back. I have installed toroids on every coax and power lead in the shack so, I don't think it's caused by RF. I have also lowered and raised the output but, no relief. However, I have noticed that it occurs less offten at lower power settings.
My G90 came with FW version 1.75 (head) and 1.76 (body) so, in an effort to clear up this issue, I upograded to version 1.79b03 to no affect. I like this new version but, the problem remains.
Any tips, tricks, cures, etc. will be appreciated.
BTW ....this problem is related to VarAC only. WinLink works great.
Thanks,
Garry
N5GLR
PS - I have a work-around for this problem. Not a "fix" but, if you have two VFO's in your rig, set one of them (A ?) to the calling frequency" and the other VFO (B ?) to your predetermined receive frequency. When CQ call is finished press the the button for the secondary VFO. It's a bit awkward but, it will work until the issue with VaraC issue is fixed.