Don, I also took the liberty to do the checks on: RP2 pin 2, and the cathodes on D16 and D17 and they all behaved like U6 pin 1: 7.4 and zero when switching between BAND+ and BAND-. 73, Byron N6UI
bviets wrote: > > Don, > I did the voltage tests and they both checked out. U6 was at 7.4, so a > little under 8, but I would imagine that is within tolerance. > 73, > Byron > N6UI > > > Don Wilhelm-4 wrote: >> >> 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:[email protected] >>>> >>>> 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:[email protected] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> >> > > -- View this message in context: http://n2.nabble.com/PLL-Reference-Oscillator-Question-tp4219007p4221974.html Sent from the [K2] mailing list archive at Nabble.com. ______________________________________________________________ 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
