[time-nuts] WTS: Efratom PTB-100 Precision Timebase

Don@True-Cal truecalservices at gmail.com
Wed Jul 11 08:54:33 EDT 2018

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.


-----Original Message-----
From: time-nuts <time-nuts-bounces at lists.febo.com> On Behalf Of ed breya
Sent: Monday, July 09, 2018 7:30 PM
To: time-nuts at 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.


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