AW: [Elecraft] K2 weird problem

[Peter Zenker]

 I just had a very similar problem at a customers K2: Without SSB board but
jumpers and C167 set, all is ok. With build in SSB board ALC sometimes
worked, sometimes not.

The failure was caused by a reversed Diode D2. Even if your Diode is not
reversed, it may have a thermal failure. Also check transistor Q1


73 de Peter, DL2FI

> -----Ursprüngliche Nachricht-----
> Von: elecraft-bounces at mailman.qth.net 
> [mailto:elecraft-bounces at mailman.qth.net] Im Auftrag von Kevin Schmidt
> Gesendet: Dienstag, 28. November 2006 19:10
> An: elecraft at mailman.qth.net
> Betreff: RE: [Elecraft] K2 weird problem
> 
> Others on the list know infinitely more than I do about how 
> the K2-KSB2 work, but from the symptoms, I would guess that 
> the KSB2 is loading down the VRFDET line so that the K2 
> thinks it isn't generating enough power.
> It then tries to up the power, gives the high current 
> warning, and drops back to 10 watts.  This would suggest 
> checking the components around Q1 on the KSB2.
> 
> 73 Kevin w9cf
> 
> >
> > Hello agn fellow Elecrafters,
> >   I still have a problem with my K2, upon cold startup. power cont. 
> > set to 5w. CW mode. when 1st x-mit . bargraph shows almost 
> no ind. but 
> > hi curent alarm, power out is 10+ watts( 40m) es after a 
> minite or 2 
> > all is backto normal with bar graph showing 5w es power out 
> is 5w es 
> > no alarm. i followed Keith Darwins suggestion es made some rework 
> > eliminators. I narrowed the problem to when the ssb brd is 
> plugged in. 
> > with ssb brd out, all is fine. I went thru a rebuild of the 
> ssb board 
> > es all parts are in proper places es no cold solder joint 
> or bridges. 
> > Problem is with ssb brd. could my problem be a faulty 
> (intermittent) 
> > IC ???
> > Any sugestions appreciated.      tnx,   Gregg WB8LZG
> 
> =-------------------------------------------------------------
> Kevin Schmidt, w9cf at ptolemy.la.asu.edu, 
> http://fermi.la.asu.edu/w9cf Department of Physics Arizona 
> State University, Tempe, AZ 85287-1504
> (480) 965-8240 Fax: (480) 965-7954
> _______________________________________________
> Elecraft mailing list
> Post to: Elecraft at 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
>