[Elecraft] K2 RF Board resistance check failure. U6 Pin 8

[Wiley Kling]

I am building a recently purchased K2, serial # 7313.  In the past few years
I have built 6 or 8 solid state kits, including a K1, without a hitch.
However, I am now having a problem that is really making me feel like a
"newbie".  

 

I am on page 62 of the manual and things have gone swimmingly until now.
All of the resistance checks (RF Board) are fine except for U6 pin 8 which
is supposed to read >100 ohms.  My reading is 38.3 ohms and I cannot locate
the problem. I have searched the Elecraft Reflector and many folks have
suffered the same problem.  Problem is, I can't find a reference as to how
anyone resolved the issue.  I have done the following things:

 

1.	Reversed the leads on my DMM.
2.	Performed the resistance checks with a second DMM.  Same results.
3.	Checked polarities on all devices. 
4.	Spent 2 full days looking for cold or bridged solder joints.
5.	I have not "lifted" and checked the resistance of all resistors as I
am in the habit of testing them before installing.
6.	I have checked the schematics and have given special attention to
the soldering and polarity of all "8B" components.  (I locate 5 schematic
areas fed from U6 Pin 8).
7.	I have checked the "Thermistor Board" to the extent I can without
removing it.  It looks to be OK visually.
8.	I have not applied power and looked for heat or smoke but I have
been tempted.
9.	I have checked for a reversed U8 regulator.

 

I would appreciate any advice that anyone might offer.  I would be truly
thankful.  Would it be helpful for me to know what resistance others show
between U6 Pin 8 and each of the 8 pins on the "Thermistor Board"?  I'm
thinking that might allow me to eliminate that board as a source of the
problem but not sure I am thinking correctly.  Thanks.

 

73, Wiley, KG4UPO