[Elecraft] K2: PLL Reference Oscillator Problem

[Don Wilhelm]

Jon,

That check of the 4 MHz reference is there to help you determine the 
correct functioning of the internal counter probe - it has nothing to do 
with the frequency, but the reading should be steady at 4000.00 MHz 
(plus or minus 1 count in the last digit).

Since your results were variable (it should show a rock solid 4 MHz), 
something is wrong with your probe or with Control Panel Q9 or Q10 and 
their associated components.  Check your soldering carefully.  If you do 
not know what a good solder connection looks like, I refer you to the 
soldering article on the Elecraft website.  A good solder connection 
looks like a 'mountain' with a concave slope to it.  If your solder 
connections are convex (look more like 'balls of solder', then the 
solder pads did not receive enough heat and you have applied excess 
solder.  Wick away the excess and be sure the solder tapers off to an 
almost invisible edge on both the solder pad and the component lead.  I 
mention this repeatedly because the most common cause of builder failure 
is excessive solder and inadequate heating of both the solder pad and 
the component leads.

You must get a good reading at the 4 MHz reference oscillator test 
before proceeding to anything else.

Yes, you could have a bad component, but that is way down on the list of 
failures.  Check the values of  RP4 and RP5 on the Control Board, and Q9 
and Q10.

73,
Don W3FPR


Jon Perelstein wrote:
> On page 47 of the manual, I was testing the frequency counter.  I put 
> the counter probe tip to the left side of C22 (actually, it wasn't 
> clear which left side, but I put it to the left facing the panel as it 
> is mounted in the radio).  The LCD was jumping all over the place, 
> from about 00200 to about 04200.  As I held it there, it tended to 
> move toward the area of 04000, but it never stabilized in any way.
>  
> I went ahead and built more of the radio to get to page 63.  When I 
> attempted the 4MHz Oscillator Calibration on pg 63, I got 0000.00.
>  
> I'm not sure where to proceed from here.  Help!!
>  
> Jon
> KB1QBZ 
>  
>
>
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