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Thank you for the replies. I ended up venting the instrument and cleaning 
the source. Problem solved. I also have a radically improved signal 
intensity relative to the quantity of gas.

andy

Andrew Schauer
Earth and Space Sciences
University of Washington
Seattle, WA 98195

206.543.6327
[log in to unmask]
http://depts.washington.edu/isolab/

On Fri, 13 Nov 2009, Horng-Sheng Mii wrote:

> Dear Andy,
>
>   We had the similar problem few months ago.  Basically this problem should 
> be also seen at DI test.  If you are sure both the reference and sample 
> bellows are not leaking.  You need to check on the RC, RW, SC, and SI valves 
> for possible leakage.  In our case, it turned out that our RW valve was not 
> closed or opened  properly.  Our problem was solved after we replaced it.
>
> Regards,
> Horng-sheng Mii
> Department of Earth Sciences
> National Taiwan Normal University
> Taipei, Taiwan
>
> ----- Original Message ----- From: "A. Schauer" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Friday, November 13, 2009 4:22 AM
> Subject: [ISOGEOCHEM] IsoPrime dual inlet signal degradation
>
>
>> Hi all,
>> 
>> We measure d18O of water using the co2 equilibration method via dual inlet 
>> on our IsoPrime. Recently, when the instrument checks maximum signal, the 
>> signal degrades so rapidly that a stable signal is never attained, crashing 
>> the instrument. It doesn't seem to be gas volume or quantity because if gas 
>> is routed to the waste pump for several minutes and then returned to the 
>> source from EITHER the sample or the reference side, signal starts at 
>> 1.16e-8A and then quickly drops off to 4 or 5e-9A. The bellows remain 
>> closed or nearly so, gas is routed to the waste pumps for several minutes, 
>> and then when it returns to the source, it starts at 1.16e-8A...clearly 
>> suggesting the gas quantity did remain constant. Suggestions? 
>> Contaminants...water? Source...filament? Thank you!
>> 
>> andy
>> 
>> Andrew Schauer
>> Earth and Space Sciences
>> University of Washington
>> Seattle, WA 98195
>> 
>> 206.543.6327
>> [log in to unmask]
>> http://depts.washington.edu/isolab/
>> 
>