Paul, Get the nylon screw. If you already have the nylon screw, then examine the area on the case around the countersink hole (top and bottom) for any burrs or pieces of metal that may be tightening against the transistor tab when you tighten the screw.
73, Don W3FPR > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of Paul T. Rubin > Sent: Friday, September 08, 2006 9:06 AM > To: elecraft@mailman.qth.net > Subject: [Elecraft] KX1 Fire Sale > > > Hello all: > > > > I had disassembled my previously operational KX1 (SN854) in > anticipation of > adding the KXB3080 option. However I realized that it would be some time > before I could get around to it, and I felt like operating. So I put it > back together, powered it up, and released the smoke. Examination showed > that a short section of V+ PCB trace just after the power switch had > vaporized. PCB traces make excellent fusible links. I measured the > resistance to ground from the far end of the trace. It was 1025 Ohms. By > now I had a pretty good idea what was going on. I repaired the trace, and > measured the same resistance at the power connector. So far so good. I > powered it up outside of the case and all is well. Now I'm real > sure what's > going on. I reassembled it into the case, and measured the resistance at > the power connector; 0.4 Ohms. Q6 was shorted to the case. I > backed off the > screw for Q6 1/8 of a turn and the short goes away. I examined > the plastic > spacer and it does not seem deformed. The insulating pad also seems fine. > I did not torque the screw to 20 foot pounds. I don't know what > to do next. > All suggestions appreciated. > > > > Thanks, > > > > Paul N8NOV > > Houston > > > > _______________________________________________ > Elecraft mailing list > Post to: Elecraft@mailman.qth.net > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com > > > -- > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.1.405 / Virus Database: 268.12.1/440 - Release Date: 9/6/2006 > > _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
