so this has been driving me nuts for about two weeks now. picked up an FT-857D off a local swap, guy said it was working fine but honestly i think he just hadnt noticed the problem. receive on all HF bands is basically dead, like S0 noise floor and nothing coming through even on 40m which should be wall to wall signals here. VHF and UHF receive works perfectly fine which is what makes this weird.

TX appears to work, hooked it up to a dummy load and the power meter shows normal output on all bands, SWR looks good. so its not a finals issue or at least doesnt seem like one. i swapped the antenna just to rule out the obvious and same result. also tried a second antenna feed line, nothing changed.

my gut says its somewhere in the RX frontend on the HF side, maybe the bandpass filter switching or the preamp section but i dont have a schematic in front of me right now. anyone dealt with this on an 857? the shared TX/RX architecture on these always makes tracing stuff a bit annoying.

had almost the exact same symptom on a friends 897D a while back, which shares a lot of the same guts. turned out to be a cracked solder joint on one of the band switching relays on the RF board. the relays on these radios are notorious for this, especially if the rig has been dropped or bounced around in a mobile install for years. worth pulling the covers and giving the RF unit a good look under magnification before you go chasing anything else. reflow those relay legs and see if anything changes. took me maybe 45 mins once i had it apart and it came back to life completely.

also check the ATT and IPO settings, i know that sounds dumb but ive seen guys chase this for days and it was just the attenuator switched in. not saying thats your issue but worth confirming before going deep into it.

the rx/tx antenna switching on the 857 goes through a set of diodes and a relay, if that relay isnt fully switching over on receive youll get exactly what you describe. tx still works because the tx path is different. check Q1017 area on the RF unit schematic if you can get hold of one, i think the Yaesu service manual is floating around on mods.dk or radiomanual.info. measure the voltage on the relay coil during RX and see if its actually being driven.