Good evening all, K2/100 #5822 started yesterday producing nearly double the requested power. Below 10W fine. 50W requested gave about 100W and max power was approaching 160W on lower bands!! I searched the reflector archive to confirm my memory of posts on the problem over the years. As suggested by Don W3FPR in the past, I replaced D16-17 with 1N4148 diodes to see what happened before delving further, fearing damage to U5 or U6. On reassembly the problem was fixed!
I checked the removed 1N5711's with a Peak DCA55 and both appeared normal (low voltage test only I suppose). Have been playing with a kit built Linear Amp Ranger (572B) recently (circuit similar to Ameritron AL-811HD) and I am suspicious that on powering down the heavy toroidal mains transformer may be producing a small 'EMP' since occasionally it freezes up a nearly G4 iMac. The antenna is either disconnected or switched to a dummy load when off- air. No recent thunderstorm activity here - midwinter. Does anyone have any ideas on how to reduce this turn-off spike, in case this is the cause? All gear is fed from UK 240V mains via surge protected power outlets. Meanwhile I will be even more vigilant with antenna disconnection and grounding. 73, Ted G7BQM ______________________________________________________________ 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
