so this has been going on for about three weeks now and i cant figure it out. mid-transmission the radio just drops out of TX, like the ALC is doing something weird or the PA is folding back, hard to tell. power output just collapses to almost nothing for maybe half a second then comes back. happens on all bands but seems worse on 40m. doesnt matter if im running 50 watts or pushing closer to 100.

i already checked the obvious stuff, antenna SWR is fine, tried two different antennas actually, reseated all the connectors on the back, did a full reset. fan is spinning, no overtemp warnings showing up on the display. i pulled the lid and nothing looks obviously burned or swollen. the finals look okay to my eye but im not really qualified to say for sure.

anyone dealt with this before on a 7300 specifically? i see some threads about the driver board being a weak point but they were all from like 2019 and the radio has been revised since then supposedly. just not sure if this is something i can chase down myself or if im looking at sending it to a service center.

had almost exactly this happen on mine about a year ago. turned out to be a cold solder joint on the PA board near the bias transistor, not something you'd see just looking at it, had to actually probe around with the rig keyed up and watch for the dropout to find it. the tricky part is it only showed up when the board was at operating temp.

what i'd do first is monitor the drain current on the finals while transmitting if you have a way to do that, either with the internal meters or an external shunt. if the current is collapsing at the same time as the power that points to the driver or bias circuit. if power drops but current stays up that's more of a filtering or impedance issue downstream. the 7300 does have a known thing where the RF board connector can develop intermittent contact but i think thats more of a receive issue than TX. honestly if you're not comfortable reflowing solder joints on SMD boards it might just be worth the service center trip, icom's authorized shops arent too bad on turnaround right now from what i hear.

wild shot here but have you checked the mic connector? i had a dropout issue that turned out to be the PTT line on the mic connector going flaky, just enough resistance to occasionally drop PTT mid-over. was maddening to find. swapped to a different mic and the problem went away for two days then came back which told me it was the jack on the radio side not the mic itself.