[Elecraft] K2 PA Failure

[Wayne Burdick]

John,

K2 PAs are generally extremely reliable, and the heat sinking is  
entirely adequate as determined by extensive temperature tests of the  
PA device itself and the heat sink. There are some 7000 K2s in the  
field and few failures.

This suggests that you may have a defective part elsewhere in the  
circuit (bias, etc.). If you have any measurements, please send them  
to us. We could also take a look at it if you wanted to send it in.

I would discourage remote mounting of the PA. This might result in HF/ 
VHF/UHF parasitics that take quite a bit of effort to eliminate.

73,
Wayne
N6KR


On Feb 16, 2011, at 12:15 PM, john petters wrote:

>
>
> -------
>
>
> Hi Folks,
> I have had another PA transistor failure in my 2003 vintage K2. The
> transistors have been replaced several times over the years and the
> board is now a mess.
> I'm planning to rebuild the PA on an external board with a proper heat
> sink mounted on the back panel of the K2. This will involve taking the
> secondary from the driver transformer on a piece of coax about 6  
> inches
> long.
>
> My query is what impedance is the secondary of T2 designed to work  
> into
> and will I have a problem taking this to the external board?
>
> I've never liked the design of the mechanical fitting of the K2 PA and
> always regarded this as the Achilles Heel of the rig.
> Suggestions appreciated.
> 73
>
>
> -- 
> John Petters
> www.traditional-jazz.com
> Amateur Radio Station G3YPZ
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