Dear Shuhei,

we had a similar problem in our 253 and indeed it was hardware.
take a look at your bellows. there is a part that looks like a nail
that moves inside  a groove. the position of the nail will tell you
what is the actual position of the bellow (by comparing the two bellows
with each other). away from the dual inlet valves is 100%
(decompressed) and towards the valves is compressed. if indeed your
bellow is stuck at 50% it would be in the middle.
in our case it was stuck at fully compressed (0%) and it probably got
to that position by repeated bellow calibration. so don't calibrate
anymore.
then, there are 3 wheels that operate the bellow. for us the problem
was that they were stuck. gently moving them by hand released them and
the bellow was back to work. (they are difficult to move by hand even
if not stuck.)
  however, the first time it happened Finnigan didn't want us to do this
ourselves and send an engineer to do it (the second time I already knew
what to do...) so you might want to talk to them first.

good luck,
hagit.


-----
Dr. Hagit P. Affek
Div. of Geological and Planetary Sci.
Caltech, MC 100-23
Pasadena, CA
phone: 626-395-2383
fax: 626-683-0621

On Jul 1, 2005, at 12:22 PM, Shuhei Ono wrote:

> Dear Isogeochemists
>
> I am using MAT 253 with ISODAT 2.0.  My left bellow is misbehaving
> since I did the bellow calibration (hardware).  It is showing bellow
> value of 100% and pressure of ~100 mbar, where my guess values from
> signal intensity are ~30 % and 50 mbar, respectively.  The program
> completely hang up when I was trying to move the bellow (by a mouse or
> by typing in a number).  I am afraid if it's really a hardware problem.
>   Any inputs will be appreciated.
>
> Shuhei
>
> --
> Shuhei Ono
> Geophysical Laboratory
> Carnegie Institution of Washington
> 5251 Broad Branch Rd., NW
> Washington, DC 20015
> tell) 202-478-8988
> Fax) 202-478-8901
> On Jun 30, 2005, at 4:14 AM, Street-Perrott F.A. wrote:
>