[Elecraft] KX1 Q6 collector shorts to ground via front cover

Sat Mar 6 01:12:01 2004

Hello All.  I have finished KX1 # 422.  Neato little radio.  I was the 
Homer Simpson of Ham Radio along the way at times while building my 
KX1.  The purpose of this posting is to share my troubles and fixes with 
all who might do as I did.

I will post each item as separate message so builders who are looking 
for a specific item can find it by the subject line [as I did when I was 
looking for help].

ISSUE:  Q6 Collector SHORTS TO GROUND after installing top cover and 
tightening down the screw through the top cover into the stand-off.

I assembled everything per the instructions and diagram [Fig 24 on Page 
53].... and the measurement shown on step 1 on page 55... measure from L3 to GND.... 
should be greater than 500 ohms..... was a dead short to GND.

I took the top cover off and looked for the short.  Couldnt find anything obvious.
I repositioned the thermal pad three times.... and then the short was cleared.  However, 
when I tightened the screw as tight as I liked... the short circuit came back.  I 
didn't like the screw being this loose.... I emailed Tech Support and Gary Surrency of Elecraft mentioned that some top covers had the beveled hole machined too deep and this was causing the screw to short out to Q6's collector.

I got NYLON screws from Mouser [p/n 561-F440.25]    These screws have a bigger beveled head than the original screws.  The larger head fit the bevel in the top cover just perfectly and I was able to tighten up the screw as tight as I liked... and no Q6 collector short to GND.

 Just to be sure that the screw wouldn't work loose...
 I used some Revlon No. 61 srew retainer [clear nail polish] on the bevel head of the
screw [not the threads].  No. 61 has worked well for me in the past for similar applications.

Anyway... I hope my experience helps someone with their KX1.  TU es 72
de Rich AE7RW             dit dit

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