Michael, If you are unable to adjust the AGC Threshold to 3.8 volts or higher with the RF gain control set fully clockwise, the first thing to check is the 8A voltage supply rail. Checking it directly on RP6 pin 3 would be the best, but if you can't get to that point with power on, check at the source U4 OUT. If that voltage is not close to 8 volts, that is the cause of your problem.
Don't be concerned with all the other points until you are able to get the voltage at U2 pin 5 up to at least 3.8 volts. BTW, the 3.8 volts may be just a starting point - you should set the optimum AGC Threshold after the receiver is working well - internal receiver noise should not activate the AGC - and the point will vary from K2 to K2. I am building 2 K2s at the moment and when I optimized the AGC, one ended up at 3.8 volts while the other was 3.65 volts. 73, Don W3FPR > -----Original Message----- > > > Dear All, > Page 47 in the (error) manual says: Adjust R1 on the > control-board to 3.8 V. > I can only reach 3.6V at pin 1 of U2 > ( R1 is fully turned counter clockwise). > With no signal at the antenna (IF-Gain MAX) i have 3.58 V at pin 1 of U2. > With iF-Gain at MIN i have the 4.6V. This seems ok. But the AGC > @Saturation > is only 4.6V, far away from the expected 6.9V. > The radio sounds good. The DC-voltage at U12, Pin 5 is only 3.8, not the > expected 5.0. > Is there anything wrong? > Thanks for your help! > > Michael, DC0ZO > K2 #4691 > > _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
