repost of K@ part II alignment and test problem

[James Caruthers]

I am still having a problem getting by the part II tests.  I did find a problem with RFC15 and replaced it but I still have a problem when I run the cal fctr on tp3.  I get a rapidly changing reading which is now in the 1080 range.

I checked d16, d17,c84, c85 and L31 per problem 235 on Appendix E page 8. The solders look good and item values are correct.

I have rechecked solders on all boards and things look good  

 Rechecked the probe per the Part I tests page 47 and get a good value of 3999.98

Does anyone have a suggestion as to what else I should check to try and find the problem
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[Don Wilhelm-4]

James,

If you do not find a frequency at TP3 near 12100 kHz, and your probe is
good, then the PLL reference oscillator is not oscillating.

Look at the schematic for the RF Board sheet 1 - all the associated
components are shown in the upper left corner to the left of U4.  At
this point, all are suspect - check and double (even triple) check the
soldering of each one.  Be certain D18, D16, D17 and Q19 are oriented
correctly (compare with the parts placement diagrams).

Nnow that you have the BFO built,  do a better check on your counter
probe function - try the counter probe in TP2 and enter the menu for CAL
FCTR - you should see the BFO frequency (4912 to 4917 kHz).  If you find
something quite different than that frequency, then either the counter
probe or Q9/Q10 on the control board may have a problem.   The BFO
signal is weaker that the initial 4 MHz check and will show up problems
with the probe/counter input circuits more readily.

73,
Don W3FPR

James Caruthers wrote:

> I am still having a problem getting by the part II tests.  I did find a problem with RFC15 and replaced it but I still have a problem when I run the cal fctr on tp3.  I get a rapidly changing reading which is now in the 1080 range.
>
> I checked d16, d17,c84, c85 and L31 per problem 235 on Appendix E page 8. The solders look good and item values are correct.
>
> I have rechecked solders on all boards and things look good  
>
>  Rechecked the probe per the Part I tests page 47 and get a good value of 3999.98
>
> Does anyone have a suggestion as to what else I should check to try and find the problem
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
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>
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>
>
>  

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[James Caruthers]

I found the problem
It was RFC14.  Never did figure out what was wrong with it but things work
after I rebuilt it.
----- Original Message -----
From: "Don Wilhelm" <[hidden email]>
To: "James Caruthers" <[hidden email]>
Cc: <[hidden email]>
Sent: Friday, February 01, 2008 7:37 PM
Subject: Re: [Elecraft] repost of K@ part II alignment and test problem

> James,
>
> If you do not find a frequency at TP3 near 12100 kHz, and your probe is
> good, then the PLL reference oscillator is not oscillating.
>
> Look at the schematic for the RF Board sheet 1 - all the associated
> components are shown in the upper left corner to the left of U4.  At this
> point, all are suspect - check and double (even triple) check the
> soldering of each one.  Be certain D18, D16, D17 and Q19 are oriented
> correctly (compare with the parts placement diagrams).
>
> Nnow that you have the BFO built,  do a better check on your counter probe
> function - try the counter probe in TP2 and enter the menu for CAL FCTR -
> you should see the BFO frequency (4912 to 4917 kHz).  If you find
> something quite different than that frequency, then either the counter
> probe or Q9/Q10 on the control board may have a problem.   The BFO signal
> is weaker that the initial 4 MHz check and will show up problems with the
> probe/counter input circuits more readily.
>
> 73,
> Don W3FPR
>
> James Caruthers wrote:
>> I am still having a problem getting by the part II tests.  I did find a
>> problem with RFC15 and replaced it but I still have a problem when I run
>> the cal fctr on tp3.  I get a rapidly changing reading which is now in
>> the 1080 range.
>>
>> I checked d16, d17,c84, c85 and L31 per problem 235 on Appendix E page 8.
>> The solders look good and item values are correct.
>>
>> I have rechecked solders on all boards and things look good
>>  Rechecked the probe per the Part I tests page 47 and get a good value of
>> 3999.98
>>
>> Does anyone have a suggestion as to what else I should check to try and
>> find the problem
>> _______________________________________________
>> Elecraft mailing list
>> Post to: [hidden email]
>> You must be a subscriber to post to the list.
>> Subscriber Info (Addr. Change, sub, unsub etc.):
>>  http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/subscribers.htm
>> Elecraft web page: http://www.elecraft.com
>>
>>
>>

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