so ive been putting this off for like a year and finally just did the mars/cap mod on my IC-7300 last weekend. mostly because i wanted to be able to tx on some of the EMCOMM frequencies that fall just outside the normal ham bands without having to do a whole song and dance every time. the mod itself is pretty straightforward, just a couple jumper pads on the main board, but getting the bottom cover off without scratching anything is honestly the most stressful part.

anyway the thing i wanted to mention is that after i did it, i noticed the ALC behavior seems slightly different when im operating near the band edges. not sure if thats psychosomatic or if the TX path actually changes a little when the expanded coverage is enabled. the audio reports i've gotten are still fine so maybe im just paranoid. also had to redo the power calibration on a couple bands because i think i bumped something while i had it open.

anyone else done this and noticed anything weird afterward? or have any other mods worth doing while the thing is already open? ive seen some stuff about the heat management and adding a small fan mod but wasnt sure if thats actually necessary for casual HF use.

the ALC thing is probably real, not in your head. from what i understand the stock firmware has some soft limiting that's tied to the band plan and when you open it up it behaves a bit differently near the edges. nothing dangerous just slightly different curve. i wouldnt sweat it unless your reports start coming back distorted.

on the fan mod — honestly for casual SSB and digital work i think its overkill. the 7300 runs pretty warm on long FT8 sessions at high duty cycle but i've had mine for 3 years, no fan, and the thermal management seems fine. now if you're running it at full power for extended periods then yeah maybe worth thinking about. i put a small piece of copper tape over the heatsink fins just to help spread a little more and that felt like enough for my use case.

did the same mod on mine about 8 months ago, no issues at all and i honestly cant tell any difference in normal operation. one thing i did while i had it open was clean out some dust and re-seat the display connector because mine had a very occasional flicker that i figured might be a loose connection. turned out it was, so that was a nice bonus fix.

the heat thing — my shack gets pretty warm in the summer and i did eventually add a small 5v fan blowing across the bottom vents, just powered off a USB port on the back. its barely audible and the idle temp dropped like 10-12 degrees according to the internal temp readout. probably unnecessary but it makes me feel better during long digital mode sessions so whatever.