[time-nuts] Efratom M3100

[EWKehren at aol.com]

Ed
Thank you for your interest. I have checked many of the circuits which is  
made easy in some cases because it is a duplication of the M100 in some 
areas  and the FRS in others. I have both for comparison. Do to the very high 
densely  packaging is it not easy to probe since some of the signals are not 
accessible. 
It comes down to the loop from the Varicap modulation diode which only  
shows a very small signal but that is what I also see on the M100, the SRD, the 
 photo cell and the AC amplifiers. There is only a very small very noisy 
signal  at the input of the phase detector, the M 100 shows a very clean 5 
volt  signal. Will next open the loop and feed exactly 10 MHz in to the  loop.
Bert Kehren
 
 
In a message dated 4/3/2012 1:08:14 A.M. Eastern Daylight Time,  
eb at telight.com writes:

I have  some SPTB-100 units, which are similar to M100 units, which 
may be similar  to yours. A few years ago, one failed to lock, 
regardless of adjustment,  and I found that one of the integrator 
capacitors in the OCXO control loop  was very leaky. I don't recall 
which one, and couldn't even identify it  because I had no exact 
schematic, but I was surprised because it was a  plastic or 
small-valued ceramic unit (and not within the high temperature  
environment of the oven), which in my experience were usually quite  
reliable.

Ed


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