Thanks Don. It's a good scope, better than my skills. I'll give it a try. I'll let you know what I find.
Regards Rich -----Original Message----- From: Don Wilhelm [mailto:[EMAIL PROTECTED] Sent: Saturday, February 18, 2006 8:40 PM To: [EMAIL PROTECTED] Cc: [email protected] Subject: RE: [Elecraft] Inoperable S-Meter Rich, Yes, those numbers look a lot more sensible, and furthermore, those DC readings seem to be close to normal. I suggest you get out your 'scope while driving the K2 with a healthy sized input signal and see if you can find any IF energy at the input of the control board U1 mixer - that should in turn produce an output signal at the output of the AGC mixer at about 155 kHz. That 155 kHz signal should pass through U2 from pin 6 to pin 7 and the AC signal should be rectified by diode D1, adding to the DC bias from the voltage at U2 pin 5 and modifying the DC level at the base of Q12 with the signal strength - stronger signals will increase the Q12 base voltage and weaker signals will allow it to drift toward the setting supplied by the DC Biasing controlled by the AGC Threshold pot setting. I don't know the capabilities of your 'scope, so I don't know how low a signal level you can measure. There is a chance that you do not have a good path between the IF takeoff point (IF OUT) after the varaible filter and the input to Control Board U1 pin 1. If your 'scope can measure small signals, it would be informative to see if the signal is getting to the AGC mixer input. Even if you cannot observe the actual signals at U1 with your 'scope, you should see the voltage at the base of Q12 increase with a steady strong signal applied to the K2 input. Once you have verified that the AGC is responding to changes in signal strength, we can look at the S-meter problem if it still is present. 73, Don W3FPR > -----Original Message----- > > Don > I thought the numbers looked high, but the regulator is not > adjustable. I measured it again and found the 5v regulator high too. Snip... _______________________________________________ Elecraft mailing list Post to: [email protected] 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
