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July 2011

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Subject:
From:
Matthew Beck <[log in to unmask]>
Reply To:
JEOL-Focused Probe Users List <[log in to unmask]>
Date:
Wed, 6 Jul 2011 13:32:15 -0500
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*

Hi Everyone,

Thanks for the input. As of now, here is where we stand...

-John ~~ There is no foreline trap. The pump itself can pull
appropriate vacuum. We tested it before installation by measuring it
while pumping on itself.

-Ritchie/Kevin/Ron ~~ I checked both thermocouples and both are
working. I have since bypassed the temperature switches so that the
system believes the DP is hot. 30 min timer still flipped.

-Clayton ~~ we have just recalibrated the pirani gauges. We will
probably end up cleaning them shortly.

-Steven ~~ We will certainly look for this. In fact, we found a leak
in a P10 tube and  we replaced them all. Thanks for the suggestion

Thanks again all for your contributions. I'll update after some more pumping.

Best,

Matt

On Wed, Jul 6, 2011 at 4:09 AM, Steven Cogswell <[log in to unmask]> wrote:
> JEOL Probe Users Listserver
>
> Moderator: Ellery Frahm, [log in to unmask], Electron Microprobe Lab,
> University of Minnesota
>
> Post a message: send your message to [log in to unmask]
>
> Unsubscribe: send "SIGNOFF PROBEUSERS" to [log in to unmask]
>
> On-line help and FAQ: http://probelab.geo.umn.edu/listserver.html
>
> * 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
> champ.
>
> 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.
>
>

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