[Elecraft] K3 #8862 unwanted sidebands

[Martin Schmiedel]

Elecrafters,

i have 2 K3's, #8862 and #2878.

Listeners using Panorama adapter gear like P3 or sdr radios report 
unwanted strong sidebands when #8862 i bought from a friend  is in use.

All is fine when #2878 is in use with same settings, power, external 
amp, antenna and same mic.

The signal itself inside the ~3khz passband is fine, both K3's sound 
about the same , all ok.

One listener said, the problem vanishes, when power is below 12W (only 
low power stage in use).

I build a K2 (#2706)  and the K3 #2878 myself, so i'm not scared to take 
#8862 apart to find the cause.

Where to begin?
TNX.

--

73, Martin