so ive been putting this off for like two years but i finally cracked open the 857D and did the mars/cap mod to open up the TX range. went smoothly actually, just the one jumper on the main board, took maybe 20 minutes including reassembly. running fine on all the bands now with no issues on the regular ham allocations.

while i had it open i also recapped the finals area because one of the electrolytics looked a little puffy, nothing dramatic but it was 12 years old so figured why not. grabbed a set of nichicon caps and swapped them all out in that section. hard to say if it made a measurable difference but i feel better about it.

the thing i actually wanted to ask about though — has anyone done the display brightness mod on the 857? the display on mine is barely readable in daylight even on max brightness, and ive seen some vague references to swapping out the backlight LED or adjusting a resistor somewhere but cant find a solid writeup. would appreciate any pointers if someone has been down that road.

yeah the display on those is notoriously dim, yaesu really cheaped out on that part. i replaced the backlight on mine maybe 4 years ago, its not a trivial job because you have to basically fully disassemble the front panel to get to the display assembly. the stock backlight is a cold cathode fluorescent which is already pretty old tech, some guys have converted to LED strips but you have to match the color temp or it looks weird.

i dont have a written procedure bookmarked but i know there were some good threads on eham and also the 857 yahoo group archive if you can dig through that. the resistor mod you mentioned is real — theres a series resistor on the backlight circuit and going slightly lower value does bump the brightness but you're also running the lamp hotter so its a tradeoff on longevity. given the age of yours id probably just convert to LED and be done with it honestly.

nice work on the recap, those old electrolytics on the 857 are definitely getting to the age where they start causing weirdness. ive seen a few come through the bench with intermittent TX power issues that turned out to be caps in that section.

cant help much on the display thing but one mod i did do on mine that was worth it was adding a small fan to the heatsink — not because it was overheating but i just do a lot of WSPR and JS8 and the duty cycle gets high. stuck a quiet 40mm Noctua in there with a simple thermistor circuit and it barely comes on but when it does it really keeps the finals happy. probably overkill for normal SSB use.