[Elecraft] K2 PA Failure

[Johnny Siu]

Hello John,

I built quite a number of K2 in the past.  The PA of K2 is fairly tough.  It is 
nothing demanding for that pair of PA transistors for an output of merely 
10-15W.

I don't think it is a good idea to build external PA board.  I do suggest you 
take a digital photo of the PCB section related to the PA.  Then send your photo 
to support at elecraft.com and seek their advice.

K2 is a very mature product and all the production bugs have been 
overcome.  Elecraft knows it inside out and can give you all the required 
support.  The beauty of Elecraft product is that most of the repair can be done 
on the field and without the trouble of sending back for repair.

You may wish to take this chance to investigate why the PA of your K2 keeps on 
failing.  It is a very unusual circumstances.

 cheers, 


Johnny VR2XMC 




________________________________
寄件人﹕ john petters <tjpost at traditional-jazz.com>
收件人﹕ Elecraft <elecraft at mailman.qth.net>
傳送日期﹕ 2011/2/17 (四) 4:15:25 AM
主題： Re: [Elecraft] K2 PA Failure



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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