Hi All, An update on the resolution of my problems with my unit. I had a component value in the R5, R6 divider on the DAC output wrong - 4.7K instead of 470R and while this had not caused any noticeable difference over the many years it had run properly it obviously became a problem in that it would no longer allow an EFC control voltage to the oscillator sufficient to keep it disciplined.  I inserted a 470R and also changed the DAC from the AD1861 that had been in for years and replaced it with a PCM61P which may or may not have been part of the solution. I also, with the help of my Son-in-law, copied the PIC16F867A microprocessor using Matlab and a Pickit 3 on to another spare PIC so now have 2 PIC's with the Auto-N function. My SIL also wrote a Terminal program that utilizes the three 5 digit numbers available from the DB9 ASCII I/O to a Terminal program.  I have attached a pic taken on my phone (not a very good one) showing just the "plot" tab results of the DACvalues and Phase detector values for each 30 second.   It shows the fairly wild gyrations at turn on of the unit and how it eventually settles down to lock.  He still has a few further enhancements to make but I found it was a very useful program. Merv  VK6BMT

Great outcome Merv. Pleased to hear it, and thanks for your feedback to the list. Regards, Lloyd ZL2LEB On Thu, 22 Sept 2022 at 01:17, Mervyn Thomas via time-nuts < time-nuts@lists.febo.com> wrote: > Hi All, > > An update on the resolution of my problems with my unit. > > I had a component value in the R5, R6 divider on the DAC output wrong - > 4.7K instead of 470R and while this had not caused any noticeable > difference over the many years it had run properly it obviously became a > problem in that it would no longer allow an EFC control voltage to the > oscillator sufficient to keep it disciplined. I inserted a 470R and > also changed the DAC from the AD1861 that had been in for years and > replaced it with a PCM61P which may or may not have been part of the > solution. > > I also, with the help of my Son-in-law, copied the PIC16F867A > microprocessor using Matlab and a Pickit 3 on to another spare PIC so > now have 2 PIC's with the Auto-N function. > > My SIL also wrote a Terminal program that utilizes the three 5 digit > numbers available from the DB9 ASCII I/O to a Terminal program. I have > attached a pic taken on my phone (not a very good one) showing just the > "plot" tab results of the DACvalues and Phase detector values for each > 30 second. It shows the fairly wild gyrations at turn on of the unit > and how it eventually settles down to lock. He still has a few further > enhancements to make but I found it was a very useful program. > > Merv VK6BMT > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe send an email to time-nuts-leave@lists.febo.com -- Please consider supporting the EFF to keep the Internet open and neutral <https://www.eff.org/files/2021/12/20/member-badge-2022b.jpg>