[Kenwood] Ref: TS-870 Sticky VFO

[Larry, K4WLS]

Thanks folks for feedback - just as I suspected, a bad optical
encoder on the VFO knob. 

I don't know exactly how the TS-870 is set-up, but sometimes
the lubricant in these things gets a bit gooey. This causes a
thin film of lubricant to stick to the holes in the daisey wheel
which prevents infared light from the emitter from getting to
the detector. For the arc where the holes are clogged, the
display/freq will not change as the VFO knob is turned.

Some of the 1996 production runs of the FT-1000MP had
clarifier (RIT) controls that developed the same problem. A
lot of folks removed the knobs and front panel to get to the
two mounting screws for the clarifier. They opened up the
little bent metal tabs that kept the housing on, cleaned out the
old lubricant, put a very thin film of sewing machine oil on the
mechanical moving parts, cleaned the lenses of the infared
emitter and detector, put it back togethor, and it worked fine.

Like I said, don't know how the TS-870 is set-up, but Cliff from
AVID said the optical encoder for the TS-870 was sealed, not 
repairable, and could not be re-lubricated. 

Since my VFO is sticking at random spots, my problem might be
the gooey lubricant. I may have been my own worst enemy. In
an effort to keep the unit cool, I kept a clip-on desk fan aimed
at the back of the rig. I am going to remove the fan, let the rig
get a little warm, and see if the problem is gooey lubricant.

Larry  K4WLS