[Elecraft] [K2] K2: KPA100 transmitted audio distortion on 80 meters

[radiotelegrapher]

Please ignore this email & respond to email of same title yesterday.  I
apologize for duplication, but I thought my earlier email was lost.  K0KK


radiotelegrapher wrote:
> 
> On 80 meters only, I have moderate distortion of transmitted SSB ouput
> from
> my KPA100.  It's not RF in shack or antenna related as I confirmed on-air
> reports by listening on another receiver while transmitting into a dummy
> load.  The distortion is present only with the KPA100 on:   At 10 Watts
> (KPA100 off), no distortion; At 11 Watts (KPA100 on), distortion, which
> gets
> no worse as I run up to 100 Watts.
> 
> The distortion is actually a loud "crack" at the start of a new word or
> syllable.  However, a continuous sound is clean.  A tuning fork by the
> mike
> modulating at full power sounds fine.  From this I suspect the TR switch
> in
> the KPA100.  Tapping components doesn't reveal anything loose.
> 
> In the archives I found reports and fixes for this exact problem. 
> However,
> my KPA100 (Rev E of January 18, 2007) already has the new components from
> the fixes:  1K added in parallel to RFC3, C31 changed to .22mF.  I also
> tried changing R4 to 39K, per Don's suggestion of 3/27/00, but no joy.
> 
> Any ideas?
> 
> -- 
> 
> Dick & Judy Lamb
> 44 Post RD
> Iowa City  IA  52245-3622
> 
> Landline 319.338.2721
> Dick's cell 319.471.3834
> Judy's cell 319.471.3822
> email Dick.Judy.Lamb at gmail.com
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