Don, I finished the amp a few weeks ago. Both the amp and the KAT100 in the EC2 have been working as they should, and I've made many QSOs, many with transmit times long enough to cause the fan to switch to the high-speed.
When I started looking for this problem, I found the transistor mounting screws loose (Forgot to check them!). After I tightened them up, the amp passed the resistance checks in the manual. J3 is correct, I checked the K2's supply voltage at the cathode-end of D9, and measured +12V. It is then blocked by D9. When I measured the KPA's power supply's no-load voltage it was at the Power Pole end of the cable, so the fuse and cable should be good. When the power supply is connected to the KPA, I measure 1.5V across J3. Measuring between ground and J3+, I see a momentary continuity indication. On a higher resistance scale, the resistance started at at >10k ohms, then reduced, eventually going through zero, and then back up to a very high resistance. It looks like the meter might be charging a capacitor (C83?). I'll check all of the soldering, and the 12PA points. Thanks! 73, Jim KO5V -----Original Message----- >From: Don Wilhelm <donw...@embarqmail.com> >Sent: Feb 7, 2019 5:43 AM >To: Jim KO5V <k...@earthlink.net>, Elecraft List <elecraft@mailman.qth.net> >Subject: Re: [Elecraft] K2: I killed my KPA100 > >Jim, > >Is this KPA100 newly assembled? Or did it work beefore? > >Your KPA100 D9 and D10 diode measurements seem to be normal. > >Check the orientation of all diodes against the parts placement diagram >in the back of the manual. > >It would appear that you have a short on the 12 volt supply input of the >KPA100 - due to a solder splash or some other problem. > >Look at all points that are labeled 12PA in the schematic. >Your ohmmeter from ground to the + terminal of J3 should show the short. >Any chance that you have assembled J3 backwards? ______________________________________________________________ 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 Message delivered to arch...@mail-archive.com
