Alan, Remove the KPA100 shield and check the diodes with your ohmmeter. There are other possible faults that could have crept into your KPA100 wattmeter circuits, but the diodes are the first suspects since that is most common. If the diodes check good, then I can help you with the additional troubleshooting.
The normal cause for the failure of D16 and D17 is a static discharge coming in on the antenna. If your antenna does not have a DC path across the feedline, that can happen when you connect the antenna if the antenna has developed a static charge from wind, rain, snow, and yes lightning. With a PL-259 UHF connector, the center conductor is normally mated in the jack before the shell, so if you had a good ground on the K2 and a static charge on the feedline, that could zap the diodes. I am not certain that is how it happened, but it is a definite possibility. Is there any way you can put an RF Choke or high value resistor (above 5000 ohms) across your antenna feedlines - if you have an RF switch in the shack, that is a good place for it. Another way is to mount the choke or resistor in a PL-259 shell and add a TEE adapter at the back of the K2 - one of the female ends of the TEE connects to the PL-259 with the resistor and the antenna connects to the other female end. 73, Don W3FPR On 12/7/2010 9:27 PM, Allen Wisbey, W1SBY wrote: > Don, > > I finally got enough time to do some more tests. The KPA100 is putting > out in excess of 100 watts on all bands when set for 30 watts. An > interesting thing though... the radio acted fine when I first started > testing, then suddenly went to bad behavior. > > So, my next question just to clarify; Replacing D16& D17 should fix it? > Also what may have happened to cause this? > You repaired and aligned this radio a couple months ago, (SSB chip was > mounted backwards). All was well until I moved my shack to a different > room. > The ONLY difference in setup was I actually grounded the radio to a > ground rod outside the new location. > > 73 de Allen, W1SBY > > On 12/4/2010 12:00 AM, Don Wilhelm wrote: >> Sorry Alan, >> That was to be directed to you, and not to James. >> >> 73, >> Don W3FPR >> >> --------------------------------------------------------------- >> >> James, >> >> Can you use an external wattmeter between the K2 and the dummy load? >> With the power control set at greater than 20 watts and less than 50 >> watts, what is the power read on the external wattmeter when you do a >> TUNE? >> If it is 100 watts or greater, then you need to replace D16 and D17 in >> the KPA100. >> >> If the actual power indicated above is in the range of 20 watts, and >> you still get the HiCur messages, you will have to do a bit more >> troubleshooting - remove the KPA100 (physically) and power the base K2 >> through the coaxial power connector and take the ouput to the dummy >> load from the BNC antenna jack. Set the power at 5 watts and do a >> TUNE. Do you see a HI CUR warning? If so, what is the actual power >> output? >> Next set the power knob to 12 watts and do a TUNE again - if you see >> HiCur and the output is less than 12 watts, you have a problem with >> the Low pass filter in the base K3 - but if it occurs on all bands, >> look for the problem at T4 rather than the low pass filter. >> >> 73, >> Don W3FPR >> >> On 12/3/2010 11:06 PM, Allen Wisbey, W1SBY wrote: >>> Hi all, >>> >>> I am having problems with my K2 after moving it from one room to >>> another. >>> K2/100 into a dummy load >>> On all bands I get a HiCur notice when I try to tune, when the PA is >>> disabled (10 watts or less) the SWR shows 1:1 OK >>> On all bands with the PA enabled (over 10 watts) I get the HiCur notice >>> and the SWR indicates a fluctuating range from 3:1 to 9.9 to one >>> depending on band and power setting. >>> In all instances the power out indication is markedly lower than the >>> setting. At 10 watts set, I show 4 watts, at 90 watts set I show 7 >>> watts. >>> I have misplaced my analog wattmeter during the moving process but my >>> LDG autotuner shows that output is actually near or above my settings. >>> Not a good diagnostic tool I know. >>> I think something has definitely gone awry, any ideas on where to start? >>> >>> Thanks, >>> Allen, W1SBY >>> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:Elecraft@mailman.qth.net >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> >> > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
