so ive been sitting on doing the mars/cap mod on my IC-706MKIIG for like two years now because i kept reading horror stories about people bricking their rigs or voiding warranties on gear they paid good money for. finally just did it last weekend and honestly it went fine but there were a couple things that tripped me up that i dont see mentioned much.

first off the jumper pads on mine were already partially done from the previous owner, which i didnt realize until i was already in there with a soldering iron and wondering why the layout didnt match the diagram i had printed out. so if you're buying used, worth checking before you assume its stock. second thing is the alignment after — i had a slight power drop on 10m that i thought was a problem but after letting it warm up for a half hour it came back to normal, probably just needed to stabilize. overall TX is clean across the expanded range, checked it with a spectrum analyzer my buddy has and no obvious spurious junk showing up.

also while i was in there i replaced the finals cooling pad because the old one looked dried out and gross. not sure if that was strictly necessary but seemed smart. anyone else done the port expansion mod on these? been thinking about the CI-V speed fix too but not sure if its worth the hassle for how i use it.

the cooling pad thing is actually a really good call, i wish i had done that when i had mine apart. those pads on older icom gear get almost crusty after a decade and the thermal transfer goes to hell. i noticed my 706 running warm and traced it back to exactly that — took it apart, replaced the pad with some decent 6W/mK stuff from a computer parts supplier and temps dropped noticeably.

on the CI-V speed mod, depends on what you're using it for. if you're running it with logging software that polls the rig a lot it can make a real difference, response just feels snappier. but if you're mostly just doing manual tuning and occasional CAT commands to change bands its probably not worth the hassle. i did it on mine and i think it helped but im also not 100% sure i did it right to be honest, i was following a scan of a scan of someone's printout from like 2003 so the image quality was pretty rough.

good write-up. one thing to add — the diagram situation on the 706 variants is genuinely confusing because theres at least three slightly different board revisions floating around and the jumper locations moved between them. i spent an embarassing amount of time staring at mine before i just started probing around with a multimeter to figure out what was actually what. old rigs, gotta love em.