PLL upgrade

[TJ Campie]

 So quite a while back, I posted on this reflector about a "problem" I was having with my K2 changing apparent frequency (not displayed) drastically based on squeezing the case. It seemed as if the BFO was moving but I eventually got it to settle down and I was just more careful.

Today I decided I would dig more into the situation because I was tired of the thing swinging all over every time I moved the radio, which is fairly often as I do go portable somewhat often. I hooked up the Freq counter to TP2 (BFO) and squeezed here and there and got the radio to behave as before but I did not notice the frequency shifting at all. The issue was not in the BFO as first thought. I looked some more and hooked up to TP1 (VFO) and saw right away what was happening. The VFO would shift by up to 10k every time I squeezed the case and eventually settle back where it was previously. With the lid off, I looked around and poked and prodded until I noticed that touching the PLL upgrade board caused the mystery behavior. I did not see anything odd on the board but I wiggled it a bit and moved it further away from the nearby IC and it finally stayed stable. I re-assembled the radio and could not get the mystery behavior to return. I have squashed the beast!

Anyway, I wonder if any others have had this problem. Hopefully this will help as I have searched but found no other references to this issue.


73, W0EA
--
TJ Campie

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[Don Wilhelm-4]

Tom,

It is good that you have localized the problem area.

That behavior is typical of a marginal solder connection.  Moving things
may have "fixed" it, but it is certain to return.  I would suggest you
re-flow the soldering on the Thermistor board (you can access it by
removing the Control Board and the Front Panel), and the connections on
the bottom of the RF board.
Use a hot (750 degF) soldering iron and add a bit of solder (actually
you will be adding flux).

73,
Don W3FPR

On 9/16/2011 10:24 PM, TJ Campie wrote:
>   So quite a while back, I posted on this reflector about a "problem" I was having with my K2 changing apparent frequency (not displayed) drastically based on squeezing the case. It seemed as if the BFO was moving but I eventually got it to settle down and I was just more careful.
>
> Today I decided I would dig more into the situation because I was tired of the thing swinging all over every time I moved the radio, which is fairly often as I do go portable somewhat often. I hooked up the Freq counter to TP2 (BFO) and squeezed here and there and got the radio to behave as before but I did not notice the frequency shifting at all. The issue was not in the BFO as first thought. I looked some more and hooked up to TP1 (VFO) and saw right away what was happening. The VFO would shift by up to 10k every time I squeezed the case and eventually settle back where it was previously. With the lid off, I looked around and poked and prodded until I noticed that touching the PLL upgrade board caused the mystery behavior. I did not see anything odd on the board but I wiggled it a bit and moved it further away from the nearby IC and it finally stayed stable. I re-assembled the radio and could not get the mystery behavior to return. I have squashed the beast!
>
> Anyway, I wonder if any others have had this problem. Hopefully this will help as I have searched but found no other references to this issue.
>
>
> 73, W0EA

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html