[time-nuts] 5061A ion pump P/S problem

[Morris Odell]

Corby,

Thanks very much for this advice. It turned out the spare unit was quite OK 
after all. It's installed as I type, and the 5061A is locked beautifully and 
showing the same freq as the Z3815A GPSDO on a HP 5345 counter. A check of 
the "flop" parameters shows the Cs tube is nice & healthy and all's right 
with the world!!!

The unit had been running with the mode switch in the "Cs off" position for 
a couple of years so the tube was well and truly pumped down. The ion 
current was very close to zero. I have a Shera controller circuit built into 
the unused battery compartment so most of the time it runs as a GPSDO but I 
like to exercise the Cesium from time to time too.

Thanks again Corby and everyone else who suggested ways to get it going 
again.

Morris

PS: my 5345 counter does not have the GPIB option so I can't do things like 
Allen plots. If anyone happens to have a junker with a GPIB card available 
I'd love to hear about it.



> From: corby d dawson <cdelect at juno.com>
> Subject: Re: [time-nuts] 5061A ion pump P/S problem
> To: time-nuts at febo.com
> Message-ID: <20080819.090934.-558537.0.cdelect at juno.com>
> Content-Type: text/plain; charset=us-ascii
>
> Morris,
>
> You implied that you tested the spare module on the bench.
>
> You must connect the -side of the supply to the case of the module as
> well as the pin. (this occurs in the unit by its connection to the
> chassis)
>
> If you don't the supply floats and you will only read about 1/2 the
> voltage out.