[Kenwood] TS-930 shaft encoder question

[Jack Parker]

I have a TS-930 (5M+ serial number) in which I have found an interesting
problem.
While adjusting the trimpots on the shaft encoder PC board I noted an
anomaly in the 'scope traces. One square-wave looks pretty good and can be
set to a 50/50 duty cycle. The other sometimes shows a square-wave, which
can be set to the 50/50 duty cycle, *but* occasionally will show an
integrated pulse triggered by the positive and negative-going edges of the
square-wave. The measurements were taken with a late-model Tek 4-channel
digital storage 'scope, so I trust the result. Plus, I repeated the
measurement several times and got the same result.

Has anyone ever seen this happen and can you explain why it is occurring?

Also, the square-waves are not close enough to 90-degrees out of phase. I do
not see where the phase relationship of the ME1 and ME2 signals can be
adjusted. Can someone provide some idea as to how this is accomplished?

Thanks, in advance,

-- 
Jack, W6NF
Silver Springs, NV
DM09ji