[Elecraft] PLL Reference Oscillator Question

[Don Wilhelm]

Byron,

Don't be too concerned about the 4 MHz oscillator calibration at this 
point in your assembly process.  Once you have completed your K2, you 
can refine the calibration - see the K2 Dial Calibration article on my 
website www.w3fpr.com for "the rest of the story".

Yes, 12650 is higher than the high end of the range should be, but 
please tell me what the low range is - while in CAL FCTR, tap BAND+ and 
tell me what the frequency is, then tap BAND- and again tell me what the 
displayed frequency is.  Perhaps I can craft an answer to the possible 
trouble spots from that information.

73,
Don W3FPR

Byron Viets wrote:
> Hello everyone.  I purchased my K2 kit about 4 years ago and as life would
> have it, I rarely have time to work on the beast except during holidays etc.
>  More time for amateur radio would sure be nice, but I'm not near retirement
> and for some reason I keep getting pesky bills in the mail.  Anyway here is
> my situation:
>
> 1) I am at the Alignment and Test, Part II portion and trying to get through
> the 4 MHz Oscillator Calibration section.
> 2) When I take a freq. measurement at TP3 for the PLL with the frequency
> probe, I get a reading of ~12650, obviously way too high.
> 3) I inspected parts, soldering etc and cannot find a fault.
> 4) Decided to do some signal tracing and performed a measurement of the
> reference oscillator signal on pin 1 of U4.  My reading is .51, instead of
> the expected 0.8-1.8. Vrms.
>
> So my question is this:
>
> It seems that the 12650 measurement is so high that it may be an indicator
> that the X1 crystal in the PLL oscillator is defective. However, with the
> low reading on pin 1 of U4 I'm not so sure about the crystal.  Could the
> increased frequency reading at TP3, cause the voltage drain on the U4 or am
> I barking up the wrong tree?
>
> I've looked through the email archives and haven't found anything quite
> similar to my issue.  I hate to start pulling stuff apart if the crystal is
> the issue and would like to hear what others think of the problem.
>   
>