[Elecraft] K2 VFO / Encoder Problem

[Don Wilhelm]

Nidge,

It is difficult to predice the exact voltage levels that will be present 
in digital signals at any particular time.  That may be why the U3 
redings may be off from what is listed in the manual.  Check by 
comparison instead.
Compare the voltage at FP U3 pin 14 with the voltage your meter reads at 
pins 7 and 15 - they should be similar.  If they are not, then it is 
likely that U3 has a damaged output at pin 14.

Additionally, check to be certain the signal at encoder pin 2 is making 
it to CB U6 pin 8 and the signal at encoder pin 3 makes it to CB U6 pin 16

73,
Don W3FPR

Nigel (Nidge) Smith wrote:
> I have in my possession a K2 that has developed a fault with 
> the encoder.
>
> When trying to tune the radio, rotating the encoder results in just
> the last digit displayed flickering back and forth.
>
> At first I thought the Optical encoder had failed and so ordered a 
> replacement from Elecraft which arrived yesterday.  Today I installed
> the new Encoder only to find that the problem still persists.
>
> I have checked and confirmed there is a 5Volt supply on pin1 of the 
> encoder, pins 2 and 3 fluctuate between 5Volt and 0.1Volt when the
> encoder is advanced or retarded. Pin 4 appears to remain at 0.1Volt.
> In the voltage charts at the back of the manual Pin 4 is connected to
> pin 14 of U3, this according to the charts should be about 3.1Volt.
>   
>