[time-nuts] Efratom Rubidium SPTB-100/LN-001 info wanted

[ed breya]

I have three of these units, and have been looking for the right 
manual for years. Thanks for this part, but I believe the SPTB is 
different from the FRK in the schematics and some of the construction 
detail - for example, since it's 5 MHz vs 10, that circuit is 
different, not just the crystal frequency. I have found other things 
in the PLL too, that probably relate to the "LN" performance.

I have managed to use the *FRK manual, which is close enough to get 
by - the circuit operation is the same, just the design details 
differ. I also had to replace a capacitor in one unit that would not 
lock - it was a leaky ceramic one in the PLL. I had to do a bit of 
guesswork and shotgunning, since the circuit topology and parts 
layout were quite a bit different in that area.

*I may be confusing it with another model - the M-100, I think, that 
is similar. This was a few years ago.

Ed