so this has been driving me nuts for about two weeks now. my 7300 is outputting maybe 30-35 watts max on 40m when i have it set to 100w, every other band hits right around where it should. checked the obvious stuff — ALC looks normal on the display, SWR on my antenna is fine, tried two different antennas just to rule that out. even borrowed a buddies wattmeter and stuck it right at the radio output so its definitely the rig and not downstream.

i bought it used about 8 months ago and its been perfect until now. no idea if it was dropped or anything before i got it. started noticing it when i was having trouble breaking a pileup on 40 and thought it was propagation but then i actually checked the power output and yeah, something is wrong.

anyone seen this on a 7300 before? im wondering if its a PA transistor issue or maybe something on the LPF board for that band. havent opened it up yet because honestly im a little nervous about voiding any warranty type stuff but i think im probably outside that window anyway. tempted to just send it to icom but the wait times i keep hearing about are rough.

yeah the 7300 has individual LPF relays for each band and those can get flaky, especially on a used radio that might have seen some abuse. before you crack it open id actually try running some diagnostics through the service menu — theres a way to force the PA to different bands and monitor the drain current. if the current looks normal but output is low on 40m specifically then you're probably looking at a relay contact issue rather than a blown transistor.

the LPF board on that radio is not terrible to get to but its not exactly plug and play either. if you go in there, the relay for 40m is pretty easy to identify. some guys just reflow the solder joints on those relays and that fixes it, others have had to actually swap the relay. Takamisawa relays are what Icom used and you can get replacements no problem. id check eHam for the service manual if you dont already have it, the alignment procedure after is pretty straightforward.

had something similar on my 7200 a while back, turned out to be a cracked solder joint on the PA board and not the LPF at all. wouldnt have found it without putting it under magnification. might be worth a look before assuming its the filter stage. just saying there can be more than one thing going on with a used radio