There was a ham in DFW area well regarded on Kenwood repairs. Not sure
he is still active.
Service manual for 850 is on internet, has schematics and assembly
drawings and photos.
The problem you have is probably bad
asian built electrolytic capacitors on the voltage bus for the display
board. I am not sure if these are on the display board or on one of the
other boards. See service manual.
Some bypassing was done with parallel bus caps, and both of the failing
caps need to be replaced at same time. if originals were rated 15 volts
put in 25 volt new ones The originals may have electrolytic leaks, or
swollen cases or ends. Clean any electrolytic leaks immediately upon
finding them or they could corrode and loosen the copper traces. Peeled
copper traces can be replaced with short lengths of tinned no. 26 solid
telephone frame wire jumpers. Run the wire to a pad of the same trace
and use clean iron tip, wet sponge wiper, and quality tin/lead solder of
thin diameter, close to that of the copper jumper. insulate the wire.
Don't use too hot an iron. 15 watts iron, cleanly soldered, should work.
If soldering in a copper run, scrape the coating from the copper trace
before soldering. Get the copper bright, then tin it.
GL, we just revitalized three shorted electro. caps on the club 850
here, at W5KA, by replacement.
-Stuart Rohre
K5KVH
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
|