[Elecraft] (no subject)

[Eric Manning]

Tom

That makes two of us with self-repairing K2s, both in the sidetone circuits.
Time to call Stephen King. And watch out  for QSL cards from people 
you don't remember working. =)

eric



  Tom Hammond  wrote:

  >Well... shoot!

  >I just managed to KILL ALL SIDETONE from my K2 as I
  >was just about to begin taking readings...!

  >I thought I might have accidently shorted Vcc (U9-7)
  >to Bypass (U9-8) as I was probing U9-8 for a measurable
  >drive level... however, the problem appears to be MUCH
  >further up the AF chain that that... I see no output
  >from U8-4 (the DAC which generates the tone when the
  >KIO2 is installed). And yes, I've already confirmed
  >that the MENU item for U8-4 sidetone source IS selected.

  >RECEIVED signals still work, so I think that U8 (LM380N-8)
  >is still working, thoung I've not tried to forcefeed
  >audio into the Bypass input, which is where the sidetone
  >is applied.

  >More later. One slip... only little lousy slip... Grrrrr!

DISREGARD EVERYTHING I JUST WROTE (above)...

I just stumbled back out to the shack, turned K2 back on,
Hit MENU ST L and voila(!)... SIDETONE...!

NO CLUE why it failed before, and why it self-healed...
I'm pretty confident of no cold joints, etc.

Anyway, back to testing...

Man, I just LOVE MAGIC!

73,

Tom  N0SS
-- 
Eric G Manning  P.Eng, ISP, F.IEEE
Nortel / NewMIC Professor of Network Performance &
New Media Innovation Centre Scientist
University of Victoria