[Elecraft] RE: K2 4039, Failing transmitter tests - PA Bias Grounded

[Don Brown]

Hi

The bases of Q7 and Q8 could be shorted through T4 if one of the bare wire windings are in the wrong hole or touching one of the other windings. C129, C130 or C137 could be bad but not likely but worth checking anyway. 

Don Brown


  ----- Original Message ----- 
  From: Nicolas Pike<mailto:nicolas at jetblackjelly.com> 
  To: elecraft at mailman.qth.net<mailto:elecraft at mailman.qth.net> 
  Sent: Saturday, July 10, 2004 9:26 AM
  Subject: [Elecraft] RE: K2 4039,Failing transmitter tests - PA Bias Grounded 


  Hi,

  Thanks everyone for the suggestions. I now have some more information to go
  on!

  Q7 Collector 3k OK!
  Q6 Base 118Ohm OK!
  Q7 Base SHORT Not OK!!!

  I have checked the diodes, toroids T1 - T4, and carefully looked over the
  board for shorts. I have referred to the circuit diagram but I do not really
  know now to determine if the PA Bias section is grounding it, or if the PA
  section is grounding itself, or some other section is grounding them!!
  (Although don't "think" much else can?)

  Wondered if you had any suggestions?

  Thanks
  Nicolas
  www.m1hog.com<http://www.m1hog.com/>


  ---
  Outgoing mail is certified Virus Free.
  Checked by AVG anti-virus system (http://www.grisoft.com<http://www.grisoft.com/>).
  Version: 6.0.716 / Virus Database: 472 - Release Date: 05/07/2004


  _______________________________________________
  Elecraft mailing list
  Post to: Elecraft at mailman.qth.net<mailto: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<http://mailman.qth.net/mailman/listinfo/elecraft>    Help:  http://mailman.qth.net/subscribers.htm<http://mailman.qth.net/subscribershtm>
  Elecraft web page: http://www.elecraft.com<http://www.elecraft.com/>