[Elecraft] Interesting KPA100 partial power control loss

[David Herring]

Does the AL-811H come with the necessary relay cable that will work with the K3, or is that an add-on purchase?  If it's an add-on, then which one would one get?  I only see YaeKenCom cables listed at Ameritron.com.

Thanks,

David, K6DCH



On Jan 23, 2010, at 11:55 AM, Ted Turk wrote:

> Good evening all,
> 
> K2/100 #5822 started yesterday producing nearly double the requested  
> power.  Below 10W fine.  50W requested gave about 100W and max power  
> was approaching 160W on lower bands!!  I searched the reflector  
> archive to confirm my memory of posts on the problem over the years.  
> As suggested by Don W3FPR in the past, I replaced D16-17 with 1N4148  
> diodes to see what happened before delving further, fearing damage to  
> U5 or U6.  On reassembly the problem was fixed!
> 
> I checked the removed 1N5711's with a Peak DCA55 and both appeared  
> normal (low voltage test only I suppose).
> 
> Have been playing with a kit built Linear Amp Ranger (572B) recently  
> (circuit similar to Ameritron AL-811HD) and I am suspicious that on  
> powering down the heavy toroidal mains transformer may be producing a  
> small 'EMP' since occasionally it freezes up a nearly G4 iMac.  The  
> antenna is either disconnected or switched to a dummy load when off- 
> air.  No recent thunderstorm activity here - midwinter.
> 
> Does anyone have any ideas on how to reduce this turn-off spike, in  
> case this is the cause?  All gear is fed from UK 240V mains via surge  
> protected power outlets.  Meanwhile I will be even more vigilant with  
> antenna disconnection and grounding.
> 
> 73,
> 
> Ted G7BQM
> 
> 
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