[Elecraft] Strange SSB transmit fault on K2

[Don Wilhelm]

Ian,

That "smells" of an intermittent carrier balance pot on the KSB2 board.  
When you rotated it, it started working,  I suspect it has nothing to do 
with the LSB/USB selection, but simply 'went right' when you changed 
sidebands.
You might want to obtain a replacement just in case it happens again.

73,
Don W3FPR

On 4/15/2013 5:26 AM, Ian Liston-Smith wrote:
> Hello all.
>
> Yesterday I noticed a tx fault on my K2 in LSB. When set to 15W, between pauses in speech, the RF rose to 5W and made sort of grinding noises when heard on a receiver. Talking reduced it, but in speech pauses it built up again over a couple of seconds.
>
> SSBA set to 1 and SSBC 2-1, although changing these settings didn't seem to make any difference.
>
> I switched to a dummy load which made no difference either, so not RF feedback I don't think. There was also what sounded like a one-second tick in the 'modulation' - from the real time clock perhaps?
>
> Selected BAL on the menu, and re-adjusted R1 on the SSB board, but the erratic levels of RF (looking on a scope across 50 ohms) didn't really dip.
>
> Switched to USB, and all ok! Got a nice dip on R1. Back to LSB, and all ok now!!
>
> Anyone any ideas what was going on? Just used it on air and it's all fine again.
>
> BTW, the earlier fault where I couldn't get anything out on SSB, and occasionally mic-through-speaker feedback was me just leaving the K2 in in BAL mode by accident!
>
> Thanks,
>
> Ian, G4JQT
>   		 	   		
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