so ive been putting this off for like two years but i finally cracked open the FT-857D last weekend to do the mars/cap mod and unlock the extended TX. not really planning to transmit outside the ham bands obviously but i wanted the flexibility for some emcomm stuff and also just to see what the rig could actually do on the lower freqs.

while i had it apart i also swapped the electrolytic caps on the PA board because a couple of them were looking a little puffy, which honestly was more concerning to me than anything else. rig is probably 12 years old at this point. while i was in there i noticed the fan runs basically constantly even at low duty cycle so im going to look at whether there's a thermistor mod or a PWM controller i can tack in there to make it temp-controlled instead. anyone done that on an 857?

also considering adding an external ALC line so i can run it more cleanly into my linear but haven't fully thought that through yet. the internal ALC on these tends to be a bit aggressive from what i've read. anyway curious if anyone else has gone down this rabbit hole with one of these rigs because there's a lot of conflicting info on the forums about the exact mod points

yeah the fan mod is totally worth doing, i did something similar on mine a while back. used a simple NPN transistor and a 10k thermistor zip tied to the heatsink, feeds into the base and gates the fan. keeps it quiet below about 45C and then it ramps up when things get warm. way less annoying on long digital modes sessions. the hardest part is finding a clean spot to grab 12v that's always on and not switching with PTT or anything weird.

on the ALC thing, i ran into the same issue driving a Tokyo Hy-Power amp. what ended up working for me was just backing the drive way down and ignoring the internal ALC entirely, then let the amp do its own thing. not elegant but it worked. never found a clean external tap point that i was happy with on the 857 specifically.

caps on the PA board is smart, those Yaesu rigs from that era used some pretty mediocre caps from what i recall reading. i redid the electrolytics on an older FT-897 and it honestly made the audio noticeably cleaner on receive which i wasnt even expecting. might be worth doing the whole board while you have it open rather than just the obviously bad ones, the others are the same age after all.