[Elecraft] K2 PLL Oscillator Range Test failure (barely)

[B. Scott Andersen]

Thanks to all who have responded on, and off, the list!
I'll check these things out tonight and let everybody
know what I discover.

-- Scott

On Jan 3, 2005, at 12:50 PM, W3FPR - Don Wilhelm wrote:

> Scott,
>
> Just to check, can you look at what the voltage swing is at U6 pins 1, 
> 2 and 3 when you do the Ref High Freq and Ref Low Freq measurements? 
> Compare to the voltage table on page 17 of Appendix E in the manual.
>
> If the voltage swings are not correct, you have a likely problem with 
> the PLL thermistor board, but if the voltage swings are correct, you 
> should look for the problem in the area of the PLL crystal and 
> varactor diodes.  First check the soldering carefully, and check all 
> components shown in the scheatic  associated with the PLL Reference 
> oscillator area (upper left corner of RF board sheet 1 of 4).
>
> If you find all is OK soldering and component wise, it may just be 
> that your crystal is not being pulled far enough.  The cure for that 
> is to change L31 to 12 uH instead of the 10 uH that is currently being 
> shipped with the K2 kits.  An e-mail to parts at elecraft.com should 
> start a new inductor on its way to you.  I believe Elecraft is still 
> providing this replacement on an 'as needed' basis, free of charge.
>
> 73,
> Don W3FPR
>
> ----- Original Message -----
>> On page 60 of the K2 manual the PLL Reference Oscillator Range Test
>> asks for the Ref. High Freq. and Ref. Low Freq. measurements. I have
>>
>> HI = 12099.67
>> LO = 12090.50
>> DIFF 9.17
>>
>> which is less than the 9.8 to 15 kHz required by the manual.
>> Everything else looks good. Any ideas? Any help would be
>> appreciated. Thanks.
>>
>
>
>
B. Scott Andersen    | "Magic is real, unless declared integer."
bsandersen at mac.com   | -- The collected sayings of Wiz Zumwalt
Acton, Massachusetts | Ham: NE1RD, QRP ARCI#11588, FP#-910