[Elecraft] K2 Won't power on

[Don Wilhelm]

Jeremy,

I can't recall a "loud buzz" condition, but I would suspect the PA 
transistors in the base K2.
First, check the resistance from the collectors of Q7 and Q8 to ground.  
If it is quite low, the PA transistors are toast - get the K2PAKIT and 
install Q7, Q8 as well as Q11 and Q13.

If the K2 will not power up, you could remove T3 (easier than removing 
Q7 and Q8) and see if it powers on.

The fact that it powers down usually indicates that too much current is 
being drawn - the resettable fuse in the K2 trips at 5 amps.

I would suggest removing T3 and then making some measurements.  Find out 
if the 8R and 8T signals are behaving properly as a first step. If 8T is 
present at the same time as 8R, that says the K2 is trying to transmit 
at the same time it is receiving.

Try isolating the DC to Q7 and Q8 (by removing T3) and then we can help 
you debug things after you get it to power up.

73,
Don W3FPR

On 2/11/2014 7:44 PM, JeremyJones wrote:
> So my K2, which has been running great for almost a year, no longer powers
> on.  I had left it powered on and connected via the serial cable to a
> computer so that I could do PSK-31 contacts remotely while I was away from
> home.  Unfortunately I never got the chance, and upon my return home, my K2
> was no longer working (no lights or any indication of life).  I shut it off
> for a couple of hours, and upon turning it back on, I got a loud buzz, then
> everything shut down again.  There was no lightning or power outages while I
> was gone, and unless the computer somehow put the radio into transmit, it
> should only have been receiving.  Any ideas on where I should start to look
> to trouble shoot this?
>
> Thanks for any help,
> Jeremy
> VA3ZTF
>