so ive had this 7300 for about 3 years now, bought it used from a guy at the club who said it was fine, and for the most part it has been but lately ive been getting this really frustrating issue where mid-transmission it just drops out. not a full shutdown, the rig stays on, ALC looks normal on the display, but RF output just goes to zero for like half a second and then comes back. happens maybe once every few minutes, sometimes less.

ive already swapped the coax, checked the PL connector on the back which looked ok, and i ran it into a dummy load to rule out the antenna. same behavior. i also noticed it seems to happen more when the rig has been on for 20-30 minutes, which makes me think thermal issue maybe? but i really dont know. anybody dealt with this before or have a starting point for me

that thermal pattern is a real clue honestly. on the 7300 specifically there was some talk on the icom reflector a while back about the PA driver stage having issues when warm — i cant remember if it was a known batch problem or just a few units but worth searching. first thing id do is pull the top cover off and run it while watching for anything that looks like a cold solder joint near the PA board. sometimes you can see them if they're bad enough, little grey ring around the joint.

also check the finals arent running unusually hot. if somethings on its way out thermally the output can get flaky before it fails completely. you could try setting power to like 30 watts and see if the dropout still happens — if it clears up at lower power thats pretty telling.

had something similar on an older 746pro and it turned out to be the power supply not the radio. was a cheap switching supply and when the rig warmed up and pulled a bit more current the voltage was sagging just enough to cause weirdness. probably not your issue if youre on a good supply but worth throwing a meter on the DC input while youre transmitting and see if it dips