[Elecraft] A Bad Thing Happened To My K2

[Don Wilhelm]

Mark,

I am puzzled since you say it transmits on 40 meters, but does not 
receive - and that it receives well on other bands.
There is precious little in the K2 that would create that situation.

What do you have set for 40 meters that is different from other bands?  
Preamp on/off? Attenuator on/off? RANT on/off?

Do you have the K160RX installed?  If so, connect your antenna to the 
receive antenna jack and see if the receiver comes to life.

Now if you could not transmit nor receive on 40 meters, I would point to 
the relay in the 40 meter lowpass filter, so check 40 meter transmit 
again - and check all bands for the maximum power produced.  Sometimes a 
transmit problem will not be revealed by transmitting at a low power 
level, but will reveal itself when the power control is cranked to maximum.

Do you have the KAT2 installed?  If so, try removing the KAT2 and see if 
you can receive 40 meters from the base K2 antenna jack.

Other than those things, I am out of ideas.

73,
Don W3FPR

Mark Saunders, KJ7BS wrote:
> This evening I had a guest ham in the shack who was curious about my K2 and
> asked if we could hook it up.  So we did.  I pointed out which 12v power
> strip, power cord, and antenna to use.  While I was getting the proper
> computer interface cables hooded up, my guest connected the radio to the
> power and switched it on.  I heard a loud snap and immediately looked in the
> direction of the K2 operating position.  My guest had a strange look on his
> face and I asked what happened.  There was a spark from the outside of the
> antenna connector on the back of the K2 to the center connector of the coax.
>
>  
>
> That can't happen, right?  Wrong.
>
>  
>
> After shutting down the power supply and inspecting things, I discovered my
> guest had wired the power backwards.  Fortunately the reverse polarity
> circuitry protected the radio and internal battery.  The radio was operating
> from the battery, that's why it came on.  I still can't understand where the
> spark came from.  However, I now have virtually NO receive on 40m, that's
> where the radio was when the spark occurred.  I have transmit and receive on
> all other bands and transmit on 40m, just no receive on 40m.
>
>  
>
> That spark killed something dealing with 40m receive.  It is so bad I can't
> even hear the local oscillator around 7000 KHz with the pre-amp on.  There
> is no CW or SSB receive.
>   
>