[Elecraft] K2 question regarding Pin 24 U6 control board operation

[Will]

Hi all,
 	This question is more to fulfill my curiosity, but maybe it has to 
do with the problem I'm experiencing with the PPL reference oscillator in 
the synthesiser section.

 	While trying to debug why I was getting a reading of 190.00 -/+ 
2KHz in the TP3 PLL reference oscillator test point, I decided to do some 
voltage checks.  I discovered that pin 2 of U5 on the RF board wasn't 
getting the 5V I was expecting according to the voltage tables.  I traced 
this all the way back to the control board, U6 pin 24.  the voltage 
reading was 0V, so thinking this is a digital output, I hooked-up a logic 
probe and confirmed the voltage reading.  I conirmed this same reading at 
pin 5 (SD0) of U4 on the RF board.

 	Now, U5 on the RF board shows 4.06V on pin 7 so maybe this is OK 
and I'm just making myself worry over a red herring...but I thought I'd 
ask.

 	On a lark, I took the boards apart and powered up the control 
board alone.  First time, pin 24 showed the correct voltage.  On second 
power-up, still outside the RF board, the pin showed 0V....maybe normal 
behaviour?

 	Anyways, I'm still looking through the RF board (redid RFC14 - one 
winding too many - and re-seated the thermister board) until I can find 
where my PLL ref problem lies.

Thanks,

Will