Todd, it sounds like a little troubleshooting is in order if you have a DMM, a screwdriver and the inclination:
1) First make certain the short is in the K3. Disconnect the K3 from the power supply and measure the resistance across the power leads going to the K3 (not the power supply). The resistance should be in the range of roughly 3K ohms. I suspect that you'll find a short (something less than 100 ohms or so). 2) Do the same thing at the back of the K3, measuring across the power pole connector on the rig with the power cable attached. If the short is still there, you have eliminated the power cord as the problem. As you said, the fuse inside the K3 is good, but it only protects part of the K3. The power amplifier module takes its power off *before* that fuse. There are one or two other small parts between the connector and the fuse. For example C31 is a bypass cap that, should it fail, would cause this problem. But that's unlikely. My next step would be to remove the KPA500 module. It's really pretty simple. You can find instructions to do it as part of this mod on the Elecraft web site: http://www.elecraft.com/manual/KPA3%20Power%20Connector%20Replacement.pdf If that eliminates the short at the K3 rear panel power pole connector know the problem is in the PA module, most likely a failed power transistor but that's not the only possibility. >From there I'd contact customer support for help. 73, Ron AC7AC -----Original Message----- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Todd brady Sent: Sunday, November 11, 2012 6:11 AM To: elecraft@mailman.qth.net Subject: [Elecraft] K3 won't power up... ??? Hello..... I was using my K3 this morning and suddenly it just shut off. I thought it may be the power supply ..... so I switched to another one. when I hook the red/black DC power cord up to power supply .... the power supply won't turn on ...... but if I unhook the power cord, the power supply will work as it should. Both power supplies work fine with my little FT 857D. I checked the fuse on the back of the K3 to see if it had been tripped .... but all seems to be ok. When I turn the power supply on ... it will turn on for a spli second and go right back off. Any suggestions on how to get the K3 to power up again ? Thanks... N4LA / Todd ______________________________________________________________ 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
