[Elecraft] K-2 Audio problem

[Don Brown]

Hi

As you describe your problem occurring with the side tone as well as the received signal I would suspect something in the AF amp circuit. Look for a bad connection, missing or wrong part around U9 on the control board. If you cannot find anything U9 may be bad. If you need to replace U9 cut all of the pins next to the body. Then using tweezers or needle nose pliers remove each pin while heating the pad. Clean out the holes with a solder sucker or tooth pick and then install the replacement IC. 


Don Brown
KD5NDB

  ----- Original Message ----- 
  From: Maxwell Moon<mailto:maxmoon at earthlink.net> 
  To: Elecraft List<mailto:elecraft at mailman.qth.net> 
  Sent: Tuesday, August 24, 2004 10:06 PM
  Subject: [Elecraft] K-2 Audio problem


  Hello,
  My K-2 audio sometimes fades completely away. It can happen whether I'm in RX or
  TX mode. (Yes, the sidetone can fade to faint or no signal.)

  Sometimes the audio comes back up almost to the original level, sometimes even
  all the way back. But it fades again before too long. And it happens with an
  external speaker or headphones, too.

  This doesn't happen when I've just powered up. In fact, it's probably always
  more than 15 or 20 minutes but I've never remembered to note the exact time.

  If the audio stays weak, I can almost always recover it by turning the AF up
  until the audio makes an odd sound, sort of like a bubble bursting. I may have
  to rotate the knob to the 3 or 4 o'clock position, and sometimes I go all the
  way & it still doesn't come back. But after it's back, it stays that way for at
  least a few minutes.

  The serial number of my K-2 is 9xx (I'm not being discrete or protecting my
  privacy--I just can't remember & don't want to climb the stairs to check on the
  rig itself ;-) It's a CW-only rig with the I/O, 160M, & NB mods. The filter
  cases were grounded, filters aligned with Spectrogram, & several other mods
  completed last year including installation of the speaker grill cloth (you don't
  suppose *that's* the problem, maybe the fabric has too tight a weave for the
  sound to get out??).

  Well, that probably tips you off to my level of RF sophistication. So, if any of
  you can suggest what I should check or look for, I'd be very grateful.

  72,
  Max, k0max


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