Hi Dave,
If you haven't already solved your diff pump problem, there is a
mechanical relay that you might also check. It is located on the
bottom of the electronics bay, under the black Plexiglass panel at
the back where all the SSR's are situated. You will also find it on
the schematics. We've had at least one or two of these go on the
SIRA's, and I think the Prism has the as well. It can be replaced
with Potter and Brumfield KRPA-11AG-240.
Hope this helps.
Cheers,
Bruce
>Hi Dave
>
>I am not familiar with the Prism but initial thoughts would be a
>water flow or pressure switch (if there is one) sticking or a
>thermal switch on the side of a diffusion pump requiring to be
>reset. Otherwise there may be a problem with the Pirani trip relay
>in the vacuum protect unit.
>
>Regards
>
>John
>
>At 12:41 12/10/2006, you wrote:
>>We recently moved our '89 vintage PRISM and cannot get high vacuum
>>back again. The analyser has pumped out normally to 1e-3 mbar but
>>the diff pumps just will not trip back on. Everything seems
>>'normal' ie all power supplies on, fuse by the rocker switch is OK
>>etc etc. Has anyone experienced this, or know of potential problem
>>areas (sticking relays, faulty switches etc) before I am forced to
>>dust off the schematics?
>>
>>Thanks for any help!
>>
>>dave
>>
>>
>>
>>-----------
>>Dave Mattey BA PhD FRAS
>>Professor of Stable Isotope Geochemistry,
>>Department of Geology,
>>Royal Holloway College,
>>University of London,
>>Egham Hill,
>>Egham,
>>Surrey,
>>TW20 0EX
>>
>>Telephone
>>
>>01784 443587 (direct line)
>> 443582 (dept secretary)
>>07780 697564 (mobile)
>>
>
>John Hill
>Mass Spectrometry Facility
>University College London
>Chemistry Department
>20 Gordon St.
>London
>WC1H 0AJ
>
>Tel: 020 7679 4605
>Fax: 020 7679 7451
--
_________________________________________________________
Bruce H. Vaughn, Senior Scientist Shipping:
Institute of Arctic and Alpine Research Attn: B. H. Vaughn
UCB 450 INSTAAR- Stable Isotope Lab
University of Colorado 1560 30th Street
Boulder, CO 80309 Boulder, CO 80303
http://instaar.colorado.edu/
http://instaar.colorado.edu/sil/
303-492-7985 voice 303-492-6388 fax
303-492-5495 lab email: [log in to unmask]
_________________________________________________________
"If there is magic on this planet, it is contained in water"
-Loren Eisley
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