so ive been running my 7300 for about two years now and overall its been a solid radio, no real complaints. but ive been seeing people talk about swapping in a better TCXO for improved frequency stability and i finally pulled the trigger on it last month. got the oscillator from a parts supplier overseas, took me like three weekends to actually get around to doing it but its done now.

honestly not sure if im just placebo-ing myself here but the rig does seem more stable on weak signal stuff, specifically when im doing JS8Call and watching frequencies drift. before the mod i felt like i was always nudging things a little, now it just kind of... sits there. hard to quantify though. didnt do any actual before/after measurements like a real person would.

also while i had it open i reflowed a couple solder joints on the PA board that looked a little cold to me, not sure if that did anything either. anyone else gone down this rabbit hole with the 7300 specifically? curious if theres other internal mods worth doing while the warranty is already thoroughly destroyed

yeah the TCXO thing is real, not placebo. the stock oscillator on those radios is fine for most HF work but if you're doing any digital modes or trying to hold tight to a frequency for an extended period you'll notice the difference. I measured mine with a GPS-disciplined reference before and after and the drift on the stock unit over a couple hours was actually pretty surprising for a radio at that price point.

as far as other mods, the one thing i keep seeing people do is mess with the fan control so it spins up earlier and keeps the finals cooler during long digital sessions. the default thermal management is a bit conservative in terms of when it kicks on but the tradeoff is the fan noise during a QSO. some guys just wire in a manual pot to control it themselves. not hard to do if you're already comfortable with the internals, which sounds like you are at this point.

i did the same mod on mine about a year ago but honestly my main motivation was just that i wanted to see if i could do it without bricking the thing lol. no real scientific method involved. cold solder joints on the PA board are actually pretty common from what ive read, worth checking those regardless of whatever else you're doing in there.