Byron, Yes, that prior response may be helpful, but all may not apply to your case - each one is different. To be specific for your problem, first monitor the voltage from RF Board U5 pin 7 while in CAL FCTR mode. When tapping BAND+, the voltage should go to about 4 volts and tapping BAND- should drop the voltage to near zero volts. If that is OK, then move on to U6 pin 1 - tapping BAND+ should produce about 8 volts and BAND- should produce nearly zero volts.
Check those conditions first. If those are all OK, then you can move on to the varactor tests, but if there is a problem with the voltages above, get back with me for additional tests and actions. 73, Don W3FPR bviets wrote: > Hi Don, > Thank you for your response. When I try the freq. range test, there is no > freq. change. I searched the reflector and found an earlier email response > authored by yourself with the subject of: K2 PLL range test SN 05233. That > person had a similar issue, so it would seem I can start tracking down the > problem based on your diagnosis in that email. > 73, > Byron > N6UI > > > > Don Wilhelm-4 wrote: > >> Byron, >> >> Don't be too concerned about the 4 MHz oscillator calibration at this >> point in your assembly process. Once you have completed your K2, you >> can refine the calibration - see the K2 Dial Calibration article on my >> website www.w3fpr.com for "the rest of the story". >> >> Yes, 12650 is higher than the high end of the range should be, but >> please tell me what the low range is - while in CAL FCTR, tap BAND+ and >> tell me what the frequency is, then tap BAND- and again tell me what the >> displayed frequency is. Perhaps I can craft an answer to the possible >> trouble spots from that information. >> >> 73, >> Don W3FPR >> >> Byron Viets wrote: >> >>> Hello everyone. I purchased my K2 kit about 4 years ago and as life >>> would >>> have it, I rarely have time to work on the beast except during holidays >>> etc. >>> More time for amateur radio would sure be nice, but I'm not near >>> retirement >>> and for some reason I keep getting pesky bills in the mail. Anyway here >>> is >>> my situation: >>> >>> 1) I am at the Alignment and Test, Part II portion and trying to get >>> through >>> the 4 MHz Oscillator Calibration section. >>> 2) When I take a freq. measurement at TP3 for the PLL with the frequency >>> probe, I get a reading of ~12650, obviously way too high. >>> 3) I inspected parts, soldering etc and cannot find a fault. >>> 4) Decided to do some signal tracing and performed a measurement of the >>> reference oscillator signal on pin 1 of U4. My reading is .51, instead >>> of >>> the expected 0.8-1.8. Vrms. >>> >>> So my question is this: >>> >>> It seems that the 12650 measurement is so high that it may be an >>> indicator >>> that the X1 crystal in the PLL oscillator is defective. However, with the >>> low reading on pin 1 of U4 I'm not so sure about the crystal. Could the >>> increased frequency reading at TP3, cause the voltage drain on the U4 or >>> am >>> I barking up the wrong tree? >>> >>> I've looked through the email archives and haven't found anything quite >>> similar to my issue. I hate to start pulling stuff apart if the crystal >>> is >>> the issue and would like to hear what others think of the problem. >>> >>> >>> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:Elecraft@mailman.qth.net >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> >> >> > > > ------------------------------------------------------------------------ > > > No virus found in this incoming message. > Checked by AVG - www.avg.com > Version: 9.0.722 / Virus Database: 270.14.120/2587 - Release Date: 12/26/09 > 03:27:00 > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
