This K2 was a bought from someone on the internet as a working unit & etc. Once received, it blew the finals in about 2 - 3 hours of QSO time. I really like the K2 but it looks it's mine to solve. I've done a lot of radoi building and RF troubleshooting down through the years, and have looked for all the usual suspects of shorts, debris shaken loose during shipment & etc.
BTW: The condition of the board and mounting hardware for the finals and PA bias transistors STRONGLY indicates that they've been changed more than a few times *before* the rig reached me . . . so , in all probability, I was probably the only one surprised by it's sudden demise. Here's what I am seeing: It has fried three sets of finals in two weeks - I changed them per the manual twice ( am a glutton for punishment ) and VERY carefully re-checked my work and metered for shorts each time. After =< 2 to 3 hours of 'normal' operation each time, the finals blew. This happened on three separate bands with an SWR of 1.2:1 (on average) at 10 Watts indicated both on my SWR/power meter and the K2 digital display. I did not notice a current warning during the last two failures and now am not certain whether I did during the first failure. Most recently: - I had finished the most recent ragchew then switched to calling CQ using a Vibroplex (as always) and heard a small 'crack' of a transistor case rupturing when immediately the 3 Amp automotive fuse in my power cord blew. The smell told me where to look. This is a relatively simple circuit and it seems to me that there is not a lot to go wrong: T4 with bad insulation ? Something in the common parts of the LGP/Band switching but not band specific? I am mystified why it would run flawlessly for a few hours of CW then let the smoke out. Anybody have ideas? I have a ton of Elecraft accessory boards on the way and that's a lot of assessories for a radio that drops dead continuously. >Ray W7ASA ..._ ._ -- View this message in context: http://elecraft.365791.n2.nabble.com/K2-Finals-Chronic-Blow-Outs-tp7564052.html Sent from the Elecraft mailing list archive at Nabble.com. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
