July 2011


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Steven Cogswell <[log in to unmask]>
Reply To:
JEOL-Focused Probe Users List <[log in to unmask]>
Wed, 6 Jul 2011 06:09:53 -0300
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Hi folks;

I'll add my two cents on this topic.  We recently had a problem with our 733
that it wouldn't switch over to the diffusion pump within the 30-minute
timespan when rough pumping, but would usually get it after restarting with
the key.   The problem actually turned out to be one of the thin-windows on
the gas-flow spectrometer counters.  Counter window had a defect was leaking
just enough P10 into the chamber to make the vacuum poor.   We replaced the
counter with one with a good window and it went back to pumping down like a

Easy way to check this is just to take the external hose off the outside of
the spectrometer and bridge it with a small piece of hose.  If it pumps down
great that way, check your interior hoses/counter.

I think our 733 gets from atmosphere to the diffusion pump switchover in
nine minutes, and we get the ready light by about 15 minutes (6 minutes
after switchover to diffusion pump).   That's from memory so I might be off
a bit.

Best regards,
Steven Cogswell, P.Eng.

On Fri, Jul 1, 2011 at 12:49 PM, Anthony J. Ruth <[log in to unmask]> wrote:

> The superprobe I am working on is having vacuum trouble. We need to run the
> roughing pump for an extended period of time to reach low vacuum and turn
> on the
> diffusion pump, but there is a timer that turns off the system if high
> vacuum is
> not reached in 30 minutes. How can I disable the timer? I have tried
> adjusting
> the potentiometers on the manual pump control panel so that all three
> pressure
> meters report high vacuum, but it still did not disable the timer.