I need help with the 1st phase of alignment on a K2, s/n 6780. Everything works perfectly with the exception of the Setting of the AGC Threshold voltage on U2, pin 5. I can only get a voltage of 3.62 volts with the R1 trimmer cap turned to it's max ccw. The manual calls for 3.8 volts and I assume with the trimmer set less than full ccw. With a regulated power supply set at 12.51v, I get 12.33 going into 8v regulator and 7.59 coming out. Both oscillators are running as shown by Heatkit IM-2420 digital freq ctr. X1 at 5.086 ant X2 at 3999.99. U2 Pin voltage follows:1 @3.1, 2 @3.1, 3 @ 3.1, 4 @ 0.0, 5 @ 3.62, 5 @ 3.62, 6 @ 3.62, 7 @ 3.62 and 8 @ 7.59.
Perhaps this is not a problem. With all the K2's built, I wonder If I'm the only one to encounter this problem. I have examined all solder joints and redone any that were not good and bright. I find no improper installed items. I checked the trimmer R1 and it operates within it's range of 5.1K ohms. I'm going to search for a "return to factory default" input in case I have screwed up the controller with some wierd setting. I have a Hayko 808 on order so I have no capability of desoldering any componets at this point. Thanks for any sugestions ahead of time. Alan Latz KA9UCP ______________________________________________________________ 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
