[Elecraft] K2 #3912

[Tom Hammond]

Hi Joe:

At 01:03 PM 4/2/04, JPalmer256@aol.com wrote:
>Problem at page 56, Resistance Checks (RF Board). U6 pin 8 measures 29 
>ohms, not over 100 as is correct.(All other resistances are okay.) I have 
>triple checked everything. Using Fluke DMM and have tried reversing leads. 
>Have several emails from Elecraft and checked all they advised. Removing 
>U8 makes no difference. I have spent days looking for a short on the 
>board. I am now advised to
>power it up and see what gets warm. Anyone have additional thoughts before 
>I do this? Thanks, Joe WA8NYX

I really don't like having to "plug 'er in and wait for smoke...".

Were it me, I'd first remove U8 (5V Reg, 78L05) and see if that fixes 
things. Could be you have it in bassackwards. And regardless, it's still 
worth checking.

Barring that, I'd then remove Ctrl Board U4 (8V Reg, LM9230T-8) and check.

Next, I'd probably start making very narrow cuts in the 8A line several 
places along it's path, in an attempt to isolate the source of the problem. 
Of course, I'd jumper each cut when I was satisfied that it was not the 
cuplrit. But, I'm not necessarily suggesting you do this since I'm nuts and 
too anal about such things to merely "plug 'er in... etc.".

73,

Tom Hammond    N0SS