Hi I'm Silvio IZ5DIY, while I was running a qrp long-wire setup by a little tuner, I touched my K2 and experienced a "electrostatic" discharge. A storm was coming and a lot of static energy was on air. I had cut - yes had to cut - external wire antenna, I was unable to remove antenna connector from K2 without discharge, or to handle the wire outdoor at the tuner connection.
After first discharge experience I switch off K2, but not disconnect... I was to much "spark". Later my cut and try to bring to ground all antenna, next I remove all connection to K2 (no more discharge). I tried to power on again and after Elecraft message the frequency was frozen. No more control or buttons working, only power know was working. I was running qrp on RTTY mode, and it is still locked in this way. I looked at this mailing list archive to see similar experience and I found something. http://elecraft.365791.n2.nabble.com/K2-freeze-at-startup-need-advice-td1099894.html#a1100892 http://elecraft.365791.n2.nabble.com/K2-CONTROL-PANNEL-FREEZE-UP-K7CJA-td3749758.html#a3749758 They lead me to a "fixed tx" behavior. Based on second link thread I check my control board focusing on U6. First I check U6 pin 30 level and it was low: 0,12v. Checked for any problem following DOT-PTT line ( CB - RF - Front): no problem. I check R value at RP4 5-6 and it was around 3K, not 82K as required. I measured level at U6: pin 25 TXD close to 5v (4,94) pin 26 RXD close to 5v pin 27 TX 0v pin 28 RX 0v pin 29 /DASH close to 5v pin 30 /DOT-PTT low 0,12v I measure Q1-Q2 collector: both close to 0v. I think if it is really "stuck on tx" I should find 8T (collector of Q1) at 8v level... but it is low. Measure at Q3-Q4 gate: both to 0v. Next test I made: removing U6 from it socket. I check again resistance at RP4 5-6 and found correct 82K. I check resistance value at different pins at U6 (alone U6) referred to pin 31 VDD U6 pin 29 - 31: high impedance U6 pin 30 - 31: 2,7K My think is U6 is gone. But it's strange it is stuck on TX without 8T level. Any guy can confirm my idea? Any more check? 73, Silvio IZ5DIY ______________________________________________________________ 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
