[Elecraft] KPA-500 HUM

[Ken Chandler]

Hi
I took part in IOTA contest at the weekend in the unassisted category, CW, high power.
The KPA-500 was used for the first full 24hrs contest here with M3i call-sign and I did give it a darn good work-out end result performance was just fab.
No hang-ups, instant power, band change, big pile-ups lots of QSO's LOTS of fun.
It just loofed along, the fan came on occasionally but was not loud, my PC's fan is louder than the amp.
HOWEVER
after the contest,  pc switched off, k3 on, amp still on in standby mode,
Their is a HUM from the amp and was fairly noticeable.
Turning off the rear switch cured it!!!
Perhaps one for the engineers to look at, as I'm sure they will, and are already on the case!!!!

Ken..G0ORH / M3i KPA-500 sn 212

Sent from my iPhone





On 3 Aug 2011, at 07:08, Klaus Koppendorfer <KK at ccf.net> wrote:

> discussion is drifting away to amplified speakers but there is realy a problem with
> HUM comming from KPA500
> 
> 1) HUM during transmit
> 2) HUM somes sometimes when the KPA500 is off, but on line and backswitch on
> 
> 
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