so this has been driving me nuts for about three weeks now. picked up a used 7300 from a guy at the club, worked fine for maybe two months then one day i noticed the ALC was pegged and output had dropped to maybe 8-10 watts on any band. tried a fresh calibration, checked the antenna port, swapped cables, even tried a dummy load just to rule out SWR stuff. same result no matter what.

the radio receives fine, no weird noises, TX audio sounds normal on the monitor, it just wont make power. display looks normal, no error codes or anything like that. fans come on when it should. i poked around inside briefly and nothing looks obviously burned, no smell, caps look ok visually at least. anyone run into this on a 7300 specifically? im wondering if its a driver stage issue or maybe one of the finals is partially gone. not sure if its worth sending to icom or finding someone local who does rig work.

had almost this exact thing happen on mine after i accidentally keyed into a open connector for a second. one of the RD15HVF1 finals had gone soft — not dead, just... weak. the other one was still pulling its weight so the radio kept functioning but output was way down. you can sometimes catch it by measuring drain current on each device separately but that means getting into the PA board which is a bit of a project on the 7300.

before you go that far though, check the PA bias trimmer. theres a known thing where those can drift, especially on units that ran hot. Icom has a service bulletin floating around on it i think, might be worth digging up. if bias is way off it'll look exactly like what you're describing. ALC pegged because the radio is trying to compensate and just can't get there.

dont overlook the RF power control setting buried in the menus, i know it sounds dumb but ive seen guys chase hardware faults for days on these things and it was just set to like 20% from a previous owner. also the ACC socket — if somethings plugged in or even if the pins are slightly corroded it can pull the power down through the external ALC line. worth a look before cracking it open further.