[Elecraft] [K2]: Low Transmitter Output

[Don Wilhelm]

  Les,

Your implication that an active device failure is a rare occurrence is 
correct.
Is your Q6 a 2N5739 or a 2N2166?  If it is a 2N5739, change R46 from the 
270 ohms value to 330 ohms to reduce the base current and also the 
heating of Q6.

73,
Don W3FPR

On 10/5/2010 8:46 PM, Les Rabe wrote:
>    I've spent the last 4 weeks or so with a problem I noticed in
> Alignment and test Part III on page 78 of the manual.  I've been
> monitoring some of the posts here which have been very helpful in
> keeping me on the right track with the debugging.  My own K2 would only
> produce 1/2 watt of output when I tuned L1 and L2.
>
> I finally realized that the current was stopping right at Q6, and after
> having spent the last 4 weeks trying to find bad solder joints and
> poorly tinned toroid leads I grabbed some courage and pulled Q6 out of
> the circuit and tested it.  It was shorted.
>
> My question is this:  What should I test to assure myself that I won't
> just burn out the new part?  It is perhaps possible that Q6 was bad all
> along or damaged during construction, but it is also possible that
> something in the circuit caused the failure.  R50 was also bad.  There
> were no sparks, smoke or burning smell anywhere when the rig was turned
> on and I haven't found any damage to suggest a major electrical event.
>
> Thanks.
>
> Les
> AB9WN
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