so ive been chasing this one for about three weeks now and im starting to lose my mind a little. my 7300 just randomly drops to like 5-10 watts output for no apparent reason. happens on all bands, doesnt seem to be temperature related because it'll do it cold, and it comes back on its own sometimes after a few minutes or i can cycle power and its fine again. no ALC weirdness that i can see on the meter, SWR is flat, and the PA temp readout looks totally normal when it happens.

i swapped the coax, checked the connectors, reseated the RF board ribbon cables as best i could without doing a full teardown. the radio is about 4 years old and i bought it used so i have no idea what the previous owner did with it. anyone run into this before? i'm wondering if its a PA transistor going soft or maybe something on the driver board. or could it be a firmware glitch? i did update to the latest firmware last month but honestly i think this was happening before that too i just wasnt paying close attention.

before i send it to Icom for a $300+ repair bill i want to make sure im not missing something dumb

had almost the exact same thing on mine about two years ago. turned out to be the final PA transistors, one of them was getting flaky and the protection circuit was throttling output to keep from blowing the whole stage. the tricky part is the protection kicks in before you see any obvious fault indication on the display so it just looks like low power with no error. icom uses RD70HVF1 finals in those and they're not terrible to source but the job is a pain if you've never done SMD rework on RF boards before.

honestly if you're not comfortable with a hot air station id just send it in. icom's turnaround was about 6 weeks for me but the repair was solid and they recapped a few things on the driver board too while they had it open. cost me around $280 including shipping both ways which sucked but the radio came back feeling like new.

worth checking if you have any voltage sag on the 13.8v line under TX. i know it sounds obvious but ive seen rigs do weird stuff when the supply dips even a little bit under load. what are you running for a power supply? some of the cheaper switching supplies have caps that go bad after a few years and they cant hold up under the current draw of the finals. throw a meter on the supply terminals right at the radio while you're transmitting and see if it stays solid. might not be the radio at all.