[time-nuts] Re: Some assistance with Ball-Efratom FRK-L Rb Osc. Needed

[Dan Rae]

Walter, at least in my FRK manual the External frequency Adjustment is 
addressed on page 4-7.  In brief you connect a 1k0 variable resistor 
between pins 8 and 9 as you have the variety with those connections.  I 
have a pencilled note saying that you may need to add some components 
internally.  The Power Supply schematic page has the details.

Personally I don't think it is worth adding; I did it to the FRK in a 
Racal 9475 standard and it has not needed attention in maybe ten years.

Best fire it up and see if it locks reasonably quickly (ten minutes?).  
There is a triangle wave that sweeps the 10 MHz oscillator as it warms 
up, if you monitor the 10 MHz output you will see the effect of that.  
There are areas that may need looking at, for example there is a free 
running CMOS oscillator around 8 kHz in the synthesiser that may have 
drifted.

Years ago there was some discussion on this list about the best supply 
voltage and heat sinking, it may be worth finding that.

Dan