A question on this subject... I had the same problem, after I installed the 100 watt amp and put everything back together. I solved it with new pads. The only symptom was a failure to develop output power. It was awhile ago. It may be that the thing refused to power-up at all, I just don't remember. There was never any smoke, no loss of the finals. When I loosened the screws holding Q7 and Q8, everything worked. After I replaced the pads, I was able to properly tighten the screws with no problem.
I have assumed there is protective circuitry so that a short to ground would not blow anything. Was I just lucky? I don't have the schematics in front of me, so I can't look to see for myself. My K2 lives a few states away. Thanks for any insights. 73 de Brian W3BW -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Terry Bassett Sent: Monday, October 04, 2004 10:39 To: [email protected] Subject: Re: [Elecraft] Question about K2's Q7 and Q8 Final Amp On Monday 04 October 2004 08:16, [EMAIL PROTECTED] wrote: > Hi, > > My K2 has been working fine but I decided to fix it anyway...hi. > The K2 manual warns that whenever the heat sink is > removed and replaced you should verify that the collectors of Q7 and Q8 are > not shorted to ground. > > Tom, WB2QDG > K2 1103 Hello Tom, The way I blew one of mine was due to a very tiny fragment of metal shaving getting installed along with the heat transfer pad of Q7, I took only a very short time to let the smoke out. This happened quite some time back, so I can't remember what I was doing or trying to accomplish, but I'd say if you've done anything to Q7/Q8 and can't find the short to ground. It "might" be something like what I did. Believe me it was a tiny, tiny fragment, but when Q7 was tightened down it made contact and did its damage. Just a bit of my experience that you can check and maybe gain from. 73, Terry KA9TXE _______________________________________________ Elecraft mailing list Post to: [email protected] 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 _______________________________________________ Elecraft mailing list Post to: [email protected] 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
