[Elecraft] [K2] SSB Failure

[Don Wilhelm]

  Tom,

My first suspicion is that the ALC is continually building as you 
speak.  You should be able to confirm that by switching the LED bargraph 
display to indicate ALC - if the ALC meter does decrease between voice 
peaks, but slowly builds up, you should see it on the bargraph.

A bad solder connection on one of the ALC components on the KSB2 board 
would cause that behavior.  Look at the lower left corner of the KSB2 
schematic to identify which components are involved.

73,
Don W3FPR

On 3/28/2011 9:55 AM, W4CU wrote:
> I bought a used K2/100, at the end of last year.  (Serial 5540 -  K2 MCU
> 2.04P, K2 IOC 1.09, KSB2  1.08, KPA100  1.10).  I mostly use CW but do
> need SSB at times.  SSB had been working fine but recently RF output
> starts out fine - folks reply to my calls - but it then fades out to
> zero after about 2 minutes of use.   The same thing happens whether I'm
> running 100 watts or 5.  If I turn the rig off for ten minutes or so it
> will again show  full output but again fades quickly to zero.  I can
> still get full output on CW even after this happens.  If anyone has any
> thoughts on simple things I might check, please let me know.  Thanks -
> Tom W4CU
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