Yaesu FT-857D VHF / UHF Final replacement

So your FT857 smells bad and has no power on VHF or UHF? Well that's not good! Chances are that the shared final transistor has let its magic smoke out and now refuses to amplify. It's not all that bad. This page is written for the 2008 ("lot 99" vintage and newer FT857 that uses a FET for the final transistor and NOT a NPN bipolar. The transistor has a few surface mounted caps along with it and depending on their condition you may want to change them out. You need to remove them to get the transistor out anyway.

Yaesu parts can be reached at 714-827-7600. Yasesu's price for the FET is kinda high. I purchased mine from RF Parts for less than half of what they wanted.
The 2008 version of the Technical Supplement is available here..... The Yaesu part number is EH007MA90D. The "D" is the revision.

To determine what "LOT" number of FT857 you have you can go to KA4CID's site that explains it all. The simple explaination is that the first number from the left is the year of manufacture. The second position is a letter that designates what month of the year the radio was made. The letters start with "C" for January and stop at "N" for December. The third and or forth numbers are the production "LOT" the radio was part of. This number is what you use to figure out what schematic you need to look at and which component is really part of the radio. The fifth through eigth positions designate where the radio fell in the sequence of all the builds of that particular "lot".

Part ID
Part Description
Industry part number
Yaesu Part Number
Yaesu Price ( Jan of 2017 )
Q3024 FET
RD70HVF1-101
G3090140
$62.36 each
   
RD70HVF1-101
$29 + $9 shipping
C3123 Chip Cap 470pf 200V
GRM2192C2D470JV01D
K22230224
New part # K22230224 $.26 each
C3124 Chip Cap 470pf 200V
GRM2192C2D470JV01D
K22230224
New part # K22230224 $.26 each
C3140 Film Cap 27pf 500V
UC232H0270J-T
K33279023
$1.78 each
C3142 Film Cap 47pf 500V
UC232H0470J-T
K33279034
$1.78 each

K2MPW at YAA Who Dot Com