Question about K2

[Aaron K5ATG]

I got a question about the Elecraft K2. A friend borrowed mine and he said
that he was running PSK31 and it just shut down on him and after that it
would no longer transmit. Once I got it back it seems to be working but not
transmitting. Am I correct in assuming that it is the PA transistors that
need to be replaced?
Thank you
Aaron K5ATG
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[Don Wilhelm]

Aaron,

It is likely that the PA transistors have failed.
Pull the top cover off and measure the voltage at the BASE of either Q7
or Q8.  During receive, it should be zero, and during transmit it should
be in the range of 0.60 to 0.64 volts.
If it is anything other than that, remove the PA transistors - get the
K2PAKIT from Elecraft, it has matched transistors.
Once you have the PA transistors removed, measure the voltage at the
solder pad for the base of Q7 or Q8 during a TUNE - if it is not in the
range of 0.60 to 0.64 volts, replace Q11 and Q13 before putting the PA
transistors back in.

If the voltages on Q7 and Q8 look good initially, then the problem is
something other than the PA transistors.  You will have to do Transmit
Signal Tracing as shown in Appendix E of the K2 manual to determine the
failing stage.  You will need the RF Probe or a 'scope with a 10X probe
to do the signal tracing.

73,
Don W3FPR

On 6/22/2017 11:37 AM, Aaron K5ATG wrote:

> I got a question about the Elecraft K2. A friend borrowed mine and he said
> that he was running PSK31 and it just shut down on him and after that it
> would no longer transmit. Once I got it back it seems to be working but not
> transmitting. Am I correct in assuming that it is the PA transistors that
> need to be replaced?
> Thank you
> Aaron K5ATG
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

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