[Elecraft] K2 Encoder problems continue.

[Don Wilhelm]

Nidge,

Is it that the last digit changes, but the K2 actually changes frequency 
(that would be a display problem) - OR - does the K2 frequency not move 
properly?

Set the K2 to 40 meters.  Put the internal counter probe into TP1 and 
set the menu for CAL FCTR.  Try moving the K2 VFO dial - does the 
frequency move with the dial movement (it normally does).
Now put the counter probe in TP3.  Tap the BAND+ button and note the 
frequency - it should be near 12,100  kHz.
Now tap the BAND- button and again note the frequency - it should now be 
near 12,085 or so, and it should stay there.

If it fails any of those tests, you have a problem with the DC voltage 
being applied to the PLL Reference Oscillator.  I can give you some 
additional points to check if that appears to be the problem.

73,
Don W3FPR

Nidge (Nigel Smith) wrote:
> Turning the dial only results in the last digit displayed flicking backward and forward.  
> Initially it was thought that the encoder was at fault and a replacement was ordered.  Unfortunately
> once the replacement was installed the problem persisted.  It was suggested by a Don (W3FPR)
> that because the voltage on pin 14 of U3 to the encoder enable pin was low
> (only 100mV or less) that the output of this drain was faulty.  Replacing the TPIC6B595N
> did not rectify the problem.
>
> I have checked continuity between the ENC-A/B outputs of the Encoder through the 
> display board and back to the MCU and all checks out OK, as does the 5Volt supply.
>
> The remainder of the front panel functions work as they should.
>
> I must admit I am completely stuck now as to what else could cause this problem, 
> especially as the radio has not missed a beat since it was constructed.
>
> Any pointers that any of you might have would be very much appreciated.
>
> Regards
>
> Nidge (G0NIG)
>
> IO93dv
>
>
> A wise man speaks because he has something to say; a fool because he has to say something
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