so this has been driving me absolutely nuts for the past month or so. my 7300 will work fine when i first fire it up, receive sounds great, noise floor where it should be. then after maybe 15-20 minutes it just goes deaf. like S-meter still moves slightly but signals that were 59 are now barely readable. transmit seems fine during this whole thing which is weird. then if i leave it for a bit or sometimes just key up a few times it comes back on its own.

i did the usual stuff, reseated the connectors i could get to, checked the antenna, swapped coax. not a coax or antenna issue because i can hear the difference between connected and disconnected so the front end isn't totally dead. just way down. my first thought was thermal issue with something in the RF board but i honestly dont know where to start poking around on these SDR-based rigs, theyre not like the old tube stuff where you could just smell which component was cooking

anyone dealt with something like this on a 7300 or similar rig? worth sending to icom or should i try to track it down myself first

that thermal intermittent pattern is a classic sign of a cold solder joint or a cap that's drifting with heat. on the 7300 specifically i'd look at the RF unit board, there's been a few reports of joints around the bandpass filter switching relays going bad. the relay driver area is worth a look too since the symptoms you describe - deaf receive but tx still working - could point to a relay not fully switching or one contact getting flaky when it expands.

before you send it anywhere, try the freeze spray method. let it get to the symptomatic state and then hit sections of the RF board with short bursts of freeze spray while watching the S-meter. when it snaps back to normal you'll know roughly where the fault is. obviously be careful around anything you could crack or short, and don't go crazy with it near electrolytics. its a bit tedious but its saved me from blind parts-swapping more than once. if you find the area you can often reflow it yourself with a decent iron and flux, these boards arent that scary once you've done a few.

had something similar on an older 746 pro years ago, turned out to be an electrolytic on the power supply section that was bulging just slightly. not obvious unless you knew to look. probably not the same root cause on your rig but the symptom of it coming back on its own after a while made me think of it. heat makes the ESR go weird and then it partially recovers when it cools a bit.

anyway icom service isnt cheap but if its still under warranty just send it. if not, the schematic and service manual for the 7300 are floating around online and its actually a pretty well documented radio compared to some of the chinese stuff ive had to deal with lately