Gil, Great to hear you found it.
73, Don W3FPR Gil Bishop wrote: > Hi Don and Gary, > > Thanks for the quick replies and you both nailed it. U6 pin1 was being > pulled down by a solder bridge on the thermistor board between the lower pad > of the thermistor and left pad of R-D. Strand of solder no more than 1/10th > the thickness of a hair. Even with the magnifier I wasn't entirely sure it > was there, but it vaporized when I hit it with the iron. Now have a nice > 13.1Khz differential between the high and low references. > Appreciate the help. I'm sure I'll be back for more! > > 73 de Gil > Ab1jv > > -----Original Message----- > From: Don Wilhelm [mailto:w3...@embarqmail.com] > Sent: Thursday, June 17, 2010 9:07 AM > To: Gil Bishop > Cc: elecraft@mailman.qth.net > Subject: Re: [Elecraft] K2 PLL Reference Osc. Range Test failed > > Gil, > > Your troubleshooting should start in the middle. Monitor the voltage at > RF board U5 pin 7 while in the CAL FCTR menu. You should see 4 volts > there when you tap BAND+ and zero volts when you tap BAND-. If that > does not happen, your problem will be found bact toward the > microprocessor, but if the voltages are as expected, your problem lies > in the forward direction, perhaps on the Thermistor board. > > Next check is at RF Board U6 pin 1. That should go to 8 volts when > BAND+ is tapped and to near zero with BAND-. If that check fails, look > for the problem on the thermistor board - usually a solder bridge - you > can reach the back of the board if you remove the control board and > front panel. > If the test is OK, then move forward - check the soldering of R19, RP3 > and D16 and D17, then monitor the voltage at RP3 pin 1 while doing the > BAND button taps , repeat at RP3 pin 3. If you have a change from 8 > volts to zero volts there, all should work - check the frequency at TP3 > when tapping the BAND buttons. > > Report your progress (or lack thereof). Tell us where it works and > where it does not. > > 73, > Don W3FPR > > Gil Bishop wrote: > >> Hi all, >> Just finished part II of the RF board assembly. (If it makes any >> difference, this is a ~6-year old never opened kit that I'm assembling, >> > ser > >> #5441, with the thermistor board mod and the PLL stability mod on the >> > bottom > >> of the board). PLL reference OSC stable at 12084.34Khz when in CAL FCTR >> mode and probe at TP3. But no deviation at all when using BAND+/- to >> > check > >> range. Haven't started to dive in yet - that's for tonight. Would >> appreciate suggestions on how/where to logically start troubleshooting >> > this. > >> 73 and thanks! >> Gil ab1jv >> >> ______________________________________________________________ >> 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 >> >> >> > > ______________________________________________________________ > 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 > > ______________________________________________________________ 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
