[Elecraft] Day 1: Fried something already?

[Don Wilhelm]

  Owen,

Most likely the bandpass filter is just fine, I will take bets that you 
effectively transmitted into an open load and something in the Low Pass 
Filter is now awry - A shorted capacitor is my first suspicion - but 
then you may have just zapped diodes in the KPA100 wattmeter.

But, break down the problem first.  If you were driving an amplifier, I 
suspect that you have the KPA100 installed (let me know if you do not).

Get out a dummy load and an external wattmeter - connect the external 
wattmeter to the K2 and connect the wattmeter to the dummy load.  Now 
power only the base K2 through the 2.1mm coaxial power connector (remove 
the APP connector from the KPA100).
Set power at 5 watts and do a TUNE.
Is the actual power output anywhere near 5 watts?, or is it above 10 
watts? (or nearly zero?) Do you get any HI CUR warnings?  How much power 
does the K2 display indicate?
Answer those questions for each band.

The answers will give an indication of where to look next.

73,
Don W3FPR

On 11/7/2010 1:35 AM, Owen B. Mehegan wrote:
> My first mistake may have been leaving the K2 turned on while I
> changed the cabling to wire up the amp. Before this I was just running
> the K2 to the antenna through my tuner. I hooked up the coax properly
> from rig to switch to amp to tuner, and then applied 12v to the
> switch. I heard a zap in my headphones, and quickly realized that I
> had hooked the DC up to the RF switch backwards : (  I disconnected it
> right away. Then I noticed that the noise level on 40m, where I had
> been tuned, was greatly reduced. I removed the amp and switch from the
> chain and connected the K2 to the tuner and antenna again. When I
> tried to tune on 40, I got a high current warning. Same on 12 and 10.
> The other bands work and sound fine.
>
> I don't know how wiring the RF detect switch backwards could have
> resulted in current getting into the K2. Maybe it was just static, I
> don't know.
>
> So I'm guessing I zapped something in the bandpass filter section of
> the K2. I've opened it up but I don't see any visible signs of trauma.
> I did smell a burnt electronics smell right after the mishap, but I'm
> pretty sure it was from the RF detect switch and not the rig. Where
> should I start with troubleshooting this?
>