My ailing K2 - Advice sought...

[Joel Kluender]

All,
   
  The other day my wife called me on the cellphone and
said, "what's that awful noise? Your speaker is making
a loud noise". I figured out that "my speaker" was the
K2, which was supposed to be off, but apparently had
been switched on by one of my kids. When I got home
and did post-mortem analysis, I determined that the
lawnmower battery that I run the K2 off of was dead,
so apparently it had been on for quite some time
without me realizing it. In addition, there is now no
audio output at all from the speaker. Dead. Nada. But
the audio through the headphones is fine and I notice
no other problems with the rig other than the speaker
audio.
   
  Before I dig deeper into the schematics and the
radio, I wanted to see if anyone else has ever had a
similar incident. Best I can tell, the audio went into
some sort of feedback loop and blew some of the
circuitry, perhaps when the suply voltage went below
the lower spec. But not being there, I am not sure the
exact sequence of events.
   
  Any suggestions? I really am in the mood to get the
K2 back to full function. Thanks in advance for the
feedback before I hit the bench with soldering iron &
multimeter in hand...
   
  73,
  Joel NF9K


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[Joe-aa4nn]

Sounds like me and others who have a faulty
headphone jack where the speaker will not
come on when the headphones are removed.
Time now to replace the headphone jack.
de Joe, aa4nn
--------------------------------------------------
----- Original Message -----
From: "Joel Kluender" <[hidden email]>
In addition, there is now no
> audio output at all from the speaker. Dead. Nada. But
> the audio through the headphones is fine and I notice
> no other problems with the rig other than the speaker
> audio.
>
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[Vin Cortina]

Joel,

May I be the one to ask the obvious question?  Have you eliminated the
speaker itself?  If the headphones work, then the audio amplifier must be
putting something out, although I realize it takes substantially less to
drive headphones.  If in fact it is part of the audio circuitry, I would
imagine it would have to be something near the "end of the line" (proximity
to the speaker) so to speak.

I know you probably have already considered this, and I apologize for citing
the obvious.  Good luck with it.

Vin  KR2F

K1-4 s/n:1977
KX1  s/n:1476



----- Original Message -----
From: "Joel Kluender" <[hidden email]>
To: <[hidden email]>
Sent: Saturday, July 22, 2006 12:05 PM
Subject: [Elecraft] My ailing K2 - Advice sought...


> All,
>
>  The other day my wife called me on the cellphone and
> said, "what's that awful noise? Your speaker is making
> a loud noise". I figured out that "my speaker" was the
> K2, ...

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[Dan Barker]

My K2 (#2456) had a similar symptom, but I was in the shack and no damage
was done. My battery had failed and was supplying 12 v idle, and about 7 v
under load (if you can call 200 milliamps a load<g>).

The noise from the speaker was VERY LOUD. Being there, I switched it off
immediately. I tried several things before swapping the power supply. That
fixed it, of course. I imagine I made the LOUD NOISE about 8 or 10 times
(I'm a slow learner<g>) of about a second each.

I have no doubt you cooked something if it went on for some time. The
speaker, most likely, if not more thingies.

Dan / WG4S

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]]On Behalf Of Joel Kluender
Sent: Saturday, July 22, 2006 12:05 PM
To: [hidden email]
Subject: [Elecraft] My ailing K2 - Advice sought...


All,

  The other day my wife called me on the cellphone and
said, "what's that awful noise? Your speaker is making
a loud noise". I figured out that "my speaker" was the
K2, which was supposed to be off, but apparently had
been switched on by one of my kids. When I got home
and did post-mortem analysis, I determined that the
lawnmower battery that I run the K2 off of was dead,
so apparently it had been on for quite some time
without me realizing it. In addition, there is now no
audio output at all from the speaker. Dead. Nada. But
the audio through the headphones is fine and I notice
no other problems with the rig other than the speaker
audio.

  Before I dig deeper into the schematics and the
radio, I wanted to see if anyone else has ever had a
similar incident. Best I can tell, the audio went into
some sort of feedback loop and blew some of the
circuitry, perhaps when the suply voltage went below
the lower spec. But not being there, I am not sure the
exact sequence of events.

  Any suggestions? I really am in the mood to get the
K2 back to full function. Thanks in advance for the
feedback before I hit the bench with soldering iron &
multimeter in hand...

  73,
  Joel NF9K


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