[Elecraft] VFO Encoder doesn't change frequency

[TI2/NA7U]

I have a very similar problem to what G0NIG posted about a year ago. Last
digit of the frequency flickers but nothing else changes when spinning the
dial. This applies also to the menu. I followed along with what Nidge had
done with Don's help and found some similar measurements, others not quite.
The final measurements were resistance measurement with and without the CB
MCU installed. After re-installing the MCU the encoder again worked,
perfectly! At each step of re-assembly I test the VFO again and it still
worked, ... until I put in place the front panel and had only tightened the
screw holding the encoder. Now it is stuck again. I figured  that I'd
re-seat the MCU again, and clean the contacts, but no joy.

My measurements on U3 on the FP board are:
Pin 14, .09v, Pin 15, 4.2V, Pin 7 3.4v.

Note: when the encoder was again briefly working these voltages were the
same! In Nidge's original thread Pin 14 was highly suspect because of the
low voltage, but when the encoder was working in my K2 the voltage was still
low.

I've checked continuity of ENC A and ENC B all the way back to the MCU, it's
good.

Resistance from each of the 4 encoder pins to Gnd:
With the CB not in place -
   Pin 1 - 24K, pin 2 - 618K, pin 3 - 617K, pin 4 - 538 K
With CB in place, and with and without the MCU plugged in the measurements
don't vary - 
   Pin 1 - 3K, pin 2 - 581K, pin 3 - 579K, pin 4 - 507K

Open to ideas.

73,

Casye

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