Thanks everyone for the insightful comments. I've been inspired by off-list help to get this unit working primarily because of the quality of the internal FRK. If nothing else, it has been a tremendous learning experience and after numerous hours studying the manual and bench testing I find myself knowing far more about optical pumping and Rb absorption lines than I thought I ever wanted to know. I keep you posted if I have a breakthrough.
Regards, Don -----Original Message----- From: time-nuts <time-nuts-boun...@lists.febo.com> On Behalf Of ed breya Sent: Monday, July 09, 2018 7:30 PM To: time-nuts@lists.febo.com Subject: Re: [time-nuts] WTS: Efratom PTB-100 Precision Timebase It's not necessarily a fault in the Rb physics - sometimes "regular" circuit or component problems cause the grief. I have three units kind of like this - "SPTB-100/LN-001," to be exact, with 5 MHz out. As I recall, it's similar to the M-100, so close enough to use some of its available schematics and info. I had a problem a few years back with one that wouldn't lock, and found that a ceramic capacitor in the VCOCXO PLL filter had gone bad - leaky, so it never settled down. I could not ID the exact circuit or part because that's one of the areas that differs quite a bit from the M-100. Replacing the cap brought it back to normal operation. I haven't searched for the "proper" manuals/schematics in a while. If anyone knows of these being available, please let me know. Ed _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.