[time-nuts] Ion pump power supply, Cs tube storage life

[Bruce Griffiths]

Tim Schulz wrote:
> Greetings again fellow listers - I have been trying to build a voltage 
> multiplier to replace what I believe to be a dead one in my 5062C ion 
> pump power supply.  I downloaded the 5061service manual (thanks 
> Leapsecond!!), and it states that it is a doubler in that power supply.  
> I long ago got rid of my HV parts stock at a ham swap foolishly thinking 
> that I wouldn't be needing them, so I had to pay $6 each for a couple of 
> NTE 2Kv PIV diodes at the local parts house.  I decided that HP might 
> have used Greinacher type doubler and put one together using some 2Kv 
> rated .01uf ceramic caps.  What I got out of it when hooked up to the 
> ion pump ps was about 1.77Kv AC according to my Fluke 8060 and high 
> voltage divider probe.  So I guess I am not quite there yet and would 
> appreciate more guidance in that area.  I did get a Bertan 5Kv 
> adjustable PS off ebay as a plan "B" if I can't fix the original 
> supply.  I also tried to dissolve the potting material on the defective 
> module, but sitting in xylol for 2 days hasn't done anything.
> Also, I was wondering if Cs tubes could be stored for long periods (say 
> 10-20 years) as long as the ion pump was kept active or at least at 
> regular intervals.  I was wondering what the failure modes might be - 
> air leakage, or does the cesium sublimate over time out of the oven?  
> Also, is anybody able to rebuild Cs tubes?  Again, I am wondering if I 
> would be able to find a replacement down the road for the compact tube 
> in the 5062.
> Thanks again!  tim
>
>   
If the potting is epoxy tetrahydrofuran may be more effective.

Bruce