K2 PLL Reference Osc Range Low

Posted by Jim KO5V on May 27, 2012; 5:50pm
URL: http://elecraft.85.s1.nabble.com/K2-PLL-Reference-Osc-Range-Low-tp7556643.html

If I have spammed everyone with multiple copies of the message, I am very sorry. I had to create a new user account, with a new email address, and my attempts were a bit clumsy. My SPAM filter my also reply to any responses, since I'm not sure if my address book copies to the new email address.

All tests and adjustments on my K2 build, up to the PLL Reference Oscillator Range Test, have been nominal. The range is low, at 9.3kHz. The PLL reference oscillator reads 12093kHz, and I adjusted C22 by zero-beating to my RX320 receiver set to 4.000Mhz.

L31 is a 12mH inductor. I swapped X1, but the range decreased, so I reinstalled the original XTAL. I went to p10 of the troubleshooting section in the manual, and found the following:

1. Reference Oscillator Output: Pin 1 of U6 measures 0.7Vrms (should be 0.8-1.8Vrms)
2. VCO Output: Pin 3 of U3, 0.25Vrms (0.30-0.40Vrms)
3. VCO Buffer Output: Pin 6 of U3: 0.55Vrms (0.60-0.75Vrms)

This was an old, unbuilt kit, S/N 212. I purchased new boards, and all parts and firmware to upgrade it to the most current specifications (new S/N 7279). I did not find anything on the Nabble archive, but I wonder if it's something to do with the thermistor board. I have double-checked my soldering. Any ideas?

Thanks in advance, & 73,

Jim KO5V
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html