so this is gonna be a long one, sorry in advance. we had a pretty nasty storm roll through about three weeks ago and i had everything unplugged except apparently i forgot the ethernet to my router and also — embarrassingly — the coax to the 7300 was still connected to the antenna switch. didn't get a direct hit or anything, there was no fireworks moment, but ever since then the radio just hasn't felt right.

the display is fine, it powers up, receives okay i think, but when i transmit on 40m the ALC is jumping all over the place and my power output is maybe 60-70% of what it used to be. i had it set to 100w and now im lucky to see 80 on a good day. on 20m it seems closer to normal which is weird. also noticed the fan seems to run more than it used to even at lower power levels.

i already checked the obvious stuff — reseated the connectors, did a full reset, checked my coax for damage. the coax going to the antenna switch actually had a little scorch mark near the SO-239 on the switch so i replaced that whole run. but the radio still acts the same way. i dont have a lot of bench equipment, just a basic multimeter and an old MFJ antenna analyzer. anyone dealt with something like this or have ideas on where to start before i ship it to Icom?

the ALC going nuts on one band but not another is a pretty classic sign that something in the PA stage took a hit. on the 7300 the finals are band-switched and there's driver circuitry that's not entirely shared across all bands, so a partial failure can absolutely show up like what you're describing. the increased fan activity tracks too — if one of the transistors is running hot or biased wrong it'll generate more heat at lower power than it should.

honestly before you ship it anywhere i'd pull the top cover off and just look. you're not going to fix it without a scope and signal generator but you might see a scorched component, a cracked board trace near the PA area, or a burned resistor. sometimes lightning damage is obvious once you look. also check around the antenna connector on the board itself, not just the coax — the center pin connection on the pcb can arc internally and look totally fine from the outside.

if you do end up sending it in, Icom's service network isn't terrible but it's not fast either. there are a couple of independent shops that specialize in Icom gear and honestly might be a better bet depending on where you are. either way get a repair estimate first because sometimes on a rig that's taken a surge hit the repair quote comes back ugly.

yeah the coax thing would have done it, an antenna switch with a scorch mark means that transient went somewhere and your radio was the most likely destination. ive seen 7300s come in for exactly this kind of thing and it's usually the PA transistors or something in the low pass filter switching that gets cooked just enough to degrade but not fail outright. the band-specific behavior is the tell.

one thing you can check without a scope — if you have any way to monitor your transmitted signal on another receiver, even a cheap SDR dongle on a dummy load tap, watch the signal quality while you key up. if you're seeing harmonics or the signal looks ragged that narrows it down. but realistically man, if the coax switch is scorched that surge went through your rig and you're probably looking at a shop visit. it might not be super expensive if it's just a transistor or two but you need someone with a proper bench to sort it out.