Shaft Encoder

[William M. Spaulding, SR]

I am working on two K2's which both have a problem.  No matter how and how hard you turn the front panel knob, the display almost moves a couple Hertz, then settles right back to where you started.  I have no clue how fix this anomaly.  I'd welcome any insight the group can offer.

Thanks,

Bill
NA7Y
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[Franki ON5ZO]

>No matter how and how hard you turn the front panel knob,
>the display almost moves a couple Hertz, then settles right back
>to where you started.
>Bill NA7Y

Bill, it depends wether it's an optical encoder or a mechanical. I assume
the latter but I am not familiar with the K2 (dreaming about K3's).

In my previous life as a broadcast engineer, I repaired a bunch of digital
audio processing devices each having a dozen of mechanical encoders. I also
repaired a friend's FT-1000MP clarifier encoder suffering the same disease.
The problem with both devices was that the grease to lubricate the shaft got
more fluid and found its way between the electrical pads and the moving
'finger' contacts. This meant that for each revolution of the shaft, not all
digital (binary) combinations were formed because the grease acts as an
insulator. So in stead of gently adjusting a parameter up or down, the
values were jumping wildly - or were not moving at all.

The solution was simple yet effective. Just be gentle with the encoder!

- Unmount the encoder.

- On the encoder (for most types), with the shaft facing away, you see 4
clips; bend them 90° upwards and CAREFULLY pull away the upper part.

- Now you see a black disk with metallic contact pads, and in your other
hand, you see the brittle contact fingers, all covered with grease (should
this be the problem).

- Clean both parts thoroughly using Q-tips with alcohol (or something
similar not agressive to plastic), but BE CAREFULL not to bend the springs.

- Now assemble everyting back together by following above steps in reverse
order, but take care of the springs when closing the encoder!

There still was plenty of grease left because there was really an excess
amount of lubricant in the shaft encoder.

I hope this might help you, should this be the cause of your problem. It
worked for me (and my employer HI).

73 de Franki ON5ZO

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