so this has been driving me nuts for about three weeks now. my ic-7300 will be mid-transmission and the tx just... stops. power meter drops to zero, rx comes back immediately, no error on screen, ALC looks normal right up until the moment it cuts out. sometimes it happens after 30 seconds, sometimes i can run a whole pile-up session no problem and then it'll do it twice in a row on the next contact.

i already swapped the coax thinking maybe i had a intermittent short somewhere but that wasnt it. PTT is via the rear ACC connector, foot switch, not the mic button, so i kinda ruled that out too but honestly im not 100% sure i should have. temperature doesnt seem to matter, happens when the rig is cold and after its been on for an hour.

anybody dealt with this before or have an idea where to poke first? i dont want to just start reflowing solder joints randomly, i'd rather actually diagnose it if possible.

had something similar on my 7300 a while back, turned out to be the ACC connector itself had a slightly bent pin that was making intermittent contact with the ground line. the radio was seeing the PTT line drop for like a millisecond and that was enough. i only found it because i wiggled the cable while keyed up and could reproduce it pretty reliably once i knew to look there.

worth trying to key up with the ACC cable completely unplugged and use the mic PTT instead, just to eliminate that whole circuit. if it doesnt drop out that way then youre probably looking at the connector or the footswitch cable somewhere. those braided footswitch cables can develop internal breaks that are basically invisible from outside.

also check if you have the RF power set anywhere near max. mine did something weird like that and it turned out to be the thermal protection kicking in even though the fan seemed fine. the fan on the 7300 isn't super aggressive and if you're doing any kind of extended digital or anything duty cycle heavy it can get warm faster than you'd think. i put a small usb fan blowing across the bottom of mine and it basically stopped happening. might not be your issue but worth noting what mode youre running when it cuts out.