so ive been chasing this fault on my 7300 for about three weeks now and im starting to lose my mind a little. the radio transmits fine most of the time, power output looks normal on the meter, but every so often — maybe once every 20-30 minutes of operating — it just drops to near zero output mid-transmission for like half a second then comes back. no warnings on screen, ALC looks normal before and after, SWR on the antenna side isnt doing anything weird.

at first i thought it was the PA running hot but the heatsink barely gets warm. tried a dummy load instead of the antenna, same behavior. swapped the mic, same thing. its not happening on any particular band either, ive seen it on 40 and 20 mostly but thats just where i spend most of my time so hard to say.

im pretty comfortable with a scope and DMM and ive poked around a bit but i dont really want to go too deep into the finals area without a clearer idea of what im looking for. anybody seen anything like this on the 7300 or similar SDR-based rigs? wondering if it could be something goofy in the RF sense chain or maybe a firmware thing but i doubt firmware causes something this consistent.

had something similar on an older 7200 years back, turned out to be a cold solder joint on one of the driver stage connectors. the symptom was almost identical — brief dropout, no fault indication, came back on its own. the intermittent nature is the giveaway really, proper failures tend to stay failed. if you can get the board out and hit the likely suspects with a reflow iron under magnification that would be my first move before going further. the PA driver area on icom gear from that era had some known issues with thermal cycling cracking joints over time, dont know if thats still the case on the 7300 but worth a look.

also check the internal fan connector if you havent, ive seen weird stuff happen when that gets flaky and the thermal management starts doing unexpected things even if temps look ok externally.

might be worth checking if there's any correlation with your power supply voltage drooping at that moment — even a brief sag can cause the rig to fold back. i had a dropout issue that drove me crazy for a month and it was the bench supply current limiting for literally milliseconds under key-down, not enough to show on a slow meter but enough to freak out the radio. threw a scope on the supply rail and saw it immediately. probably not your issue if youre on a good supply but worth ruling out quick before going deeper into the rig itself.