I've been doing ft8 lately and notice that after several hours, the radio doesn't transmit. Connected a dummy load = nothing. Sometimes, after a rest, it will start to function again. It's behaving like a heat problem. This is all on HF; the VHF and UHF are fine even when the HF quits. I'm a bit new to ham radio. Do bad finals act this way? I thought they would just fail, sort of like output transistors in an audio power amp.
I turned it on this morning and it worked fine. So today is a day of trouble shooting, checking fan operation and temperature over time.
Anyone had a similar problem?
Thanks
KC3NEJ