[Elecraft] Day 1: Fried something already?

[Owen B. Mehegan]

Hello Don, thanks for your prompt reply (again - you helped me  
diagnose my misplacement of C6 in the BPF section a couple of weeks  
back).

I do not have the KPA100, just a base K2 with the SSB module added. I  
was using an external Tokyo Hy-Power amp when this mishap occurred.

I've just done the test you described, with a wattmeter and a dummy  
load. It's not as bad as I thought at first - only 40 seems affected.  
No matter what power setting I choose on 40, when I press TUNE the K2  
shows a high current warning, and then about .4 watts output, and the  
needle on the wattmeter doesn't even flicker. All other bands can put  
out their usual amounts of power with no problems.

--
owen at nerdnetworks.org (Owen B. Mehegan)
'I spent a lot of money on booze, birds and fast cars. The rest I just  
squandered.'
   --George Best



On Nov 7, 2010, at 4:59 AM, Don Wilhelm wrote:

> 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?
>>
>