[Elecraft] K2 problems after lightning

[Don Wilhelm]

Ian,

It may be a challenge, but can be resolved by doing some orderly 
troubleshooting.  Hopefully, you will not jump around and try to 
'shotgun' it - in this case, I think that will only lead to frustration 
and perhaps incorrect conclusions.

Perhaps with a little work on your part and the benefit of your other 
K2, we can get to the bottom of things.
First of all, the most likely thing to have been damaged is the MCU - 
hopefully you have the same level firmware in both K2s, and you can swap 
between them to check - but I only mention that at this point, do not do 
any swapping first, we need to 'set the stage' for further troubleshooting.

You first want to remove the KSB2 and the K60XV.  Install jumpers in the 
headers - J9 and J10 between the two outside pins, and a .001 uF 
capacitor between J11 pin 7 and pin 12.
The K60XV removal requires a 4.7 uF capacitor between pins 1 and 3 of 
J15 and a wire jumper between J13 pins 3 and 5.

First check your key for shorts at both the dot and dash contacts with 
an ohmmeter.  It is normal for a K2 to go into transmit as the key plug 
is inserted, so check the key first and then plug it in before powering on.
Does the K2 power up in receive or in transmit?  If receive, then it is 
OK to go on(skip the next paragraph), but if not, stop, power down and 
check out the key lines from the inside of the K2 (do not remove the key 
plug) as follows.
If it goes immediately to transmit, remove the left side panel and check 
the resistance to ground at the rearmost end of R1 and R2 - which one is 
showing zero ohms?  If neither, then close the dot side of the paddle - 
one but not both should go to zero ohms - do the same for the other paddle.
All OK?  If so, the key jack is acting like it should.

Next, remove the capacitor from J11 (the SSB header).  The K2 will not 
transmit without it and no harm will come to the PA transistors with a 
long period in transmit.
Close one side of the paddles for a short string of dots or dashes as 
heard from the sidetone.  Does it go back to receive?  If so, try the 
other paddle, it should also go back to receive when you release the paddle.
If it goes to transmit and stays there, check the DC voltages at the 
anodes of D6 and D7 (this is just a check to see what is going on, it is 
not the problem).  In RX, D7 should have near zero volts and D6 near 8 
volts.  The opposite should be true for TX (use TUNE to check for that, 
it is constant rather than dots or dashes).

OK, that is enough information to tell me where you should head next to 
solve the problem.
Rather than cluttering up the reflector with troubleshooting that may 
not apply to anyone else, you may want to take it off-line and report 
the results back to the list after the problem has been solved.

We will get to the bottom of it with enough checking in the right places.

73,
Don W3FPR


On 4/6/2014 4:45 PM, Ian Liston-Smith wrote:
> Not a direct hit via the antenna, but the random wire was unplugged, lying on the bench close the the Morse key, through which it discharged!! It took a while for me to identify the 'Tick, tick, tick' which were sparks from the antenna plug jhumping to the Morse key, and not necessarily the grounded bit.
>
> My S/N 6905 K2 has 60m, noise blanker and 160m accessories.
>
> >From switch on, receiver seems to be functioning normally, all receiver function buttons and controls K2 receiver appear to operate.
>
> There is no response at all from the MENU button.
>
> Symptoms in CW mode:
>
> Plug key in and K2 goes immediately into CW tx mode as key jack contacts are made, and stays in tx mode. Power is variable by power control. All controls inoperable until switch off-on, and K2 back in rx mode until key is inserted again.
>
> Off-on then pressing TUNE button puts out RF momentarily then drops to nothing. Display stuck showing P 0.1 or some random power level. All controls inoperable until off-on.
>
> Presumably when the static got in through the key it did something nasty to some solid-state devices and/or capacitors.
>
> I have a no-accessory K2 to use as comparison, but don't know where to start or what to measure. I can swap bits around, but I'm reluctant to do that in case some faulty board or IC  does damage on the working K2.
>
> This could be a challenge...
>
>