I've never had this happen, but it sounds suspiciously like an
electronic/power or computer control/communication issue. Does anything
else seem unusual? Valves opening ok? Signal to the MS? If you have
schematics for the MS (or follow the leads from the bellows), track down and
check the bellow/electronics control card. What type of spec? Maybe I can
check ours for comparison.
College of Oceanic and Atmospheric Sciences
Oregon State University
From: Stable Isotope Geochemistry [mailto:[log in to unmask]] On Behalf
Of Jim Palandri
Sent: Friday, November 06, 2009 3:00 PM
To: [log in to unmask]
Subject: [ISOGEOCHEM] Bellows problem 253
So we just had a prolonged power outage. Since the powers that be actually
gave us heads up this time, we powered down the instrument beforehand. At
that time both bellows were at 100%, and P was 15 in the right bellows.
After starting up again, P still 15 in the right bellows, but isodat says
both bellows are now at 0%. Trying to increase the volume, the indicators
always pop back to 0%. No movement of the gears when attempting this.
Bellows hardware calibration takes about two seconds to state calibration
successfully completed, which is clearly a lie. No movement of gears when
attempting this either.
We always balance bellows pressure manually, but just for grins we had a
sequence do auto pressure balance. This causes isodat to crash to the point
where only a reboot will fix it.
In the past the sample bellows display would sometimes stick at 100%, and to
fix it I would pull the o-ring belt off of the potentiometer pulley, spin
the pulley all the way clockwise, and then do a bellows calibration. (I
fixed this for good about a year ago by cleaning the belt and pulleys as
best I could with ethanol to minimize o-ring belt slippage). I don't think
this is the problem this time, because it didn't work, and especially since
it happened to both bellows at the same time.
Department of Geological Sciences
1272 University of Oregon
Eugene, OR 97403-1272