so ive had this 7300 for about 3 years and lately its been running low power across the board, doesnt matter what band. ALC looks normal on the display, the meter shows maybe 28-32w when im pushing it to full output. RF gain is fine, tried different antennas, swapped coax, same deal. mic gain and compression settings havent changed. the radio doesnt run hot or anything weird, fan comes on normally, no error codes showing up.

i pulled the bottom cover and had a look around, nothing obviously burnt or smelling funny. my suspicion is something in the driver stage or maybe one of the finals is starting to go but im not sure how to isolate which one. i have a decent scope and a signal tracer but i havent cracked into the rf board yet because frankly icom's service manual for this thing is kind of dense and i dont want to make it worse.

anyone been down this road with a 7300 or similar SDR-based rig? curious if theres a known weak point or if i should just send it to a tech. the radio still works fine otherwise, decodes FT8 great, receive is perfectly normal.

had basically the same symptoms on mine a while back. ended up being the PA bias drifting way out of spec. icom sets those finals pretty carefully at the factory and if the bias trim pot creeps over time the output just quietly drops. before you go poking at the driver stage i'd check the PA bias first, its a much easier starting point and you wont need to unsolder anything. the service manual does have the procedure for it, its tedious but straightforward if you have a decent dummy load and a power meter you trust. mine was reading almost 20% low, adjusted it back and i was right back at 100w.

that said if the bias checks out fine then yeah it could be a driver transistor starting to degrade. the 7300 uses a two-stage setup before the finals and ive seen the driver stage go soft without completely failing. you'd want to inject a known signal level and trace through to see where you're losing gain. but honestly try the bias thing first, saved me a lot of time.

might also be worth checking your power supply if you havent already. i know it sounds obvious but i chased a low power issue on a different rig for two weeks before realizing my supply was sagging under load. not saying thats definitely it but 28w is a pretty specific kind of low that can also come from the radio throttling itself if it sees voltage drop. what are you running it off of?