Hi Penny,
You might try to run the system on a lower HV setting to possibly
confirm that conduction/arcing appears in the source assembly running at
higher HV setting.
Arnie Santos
Specialist - Instrument
Analytical Service Laboratories
International Rice Research Institute
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phone (632) 845 0563 ext 2374
-----Original Message-----
From: Stable Isotope Geochemistry [mailto:[log in to unmask]] On
Behalf Of Feng Lu
Sent: Friday, August 29, 2008 12:46 AM
To: [log in to unmask]
Subject: Re: [ISOGEOCHEM] Electronics trouble.
Ben, as the analysis goes on, this problem may occur if too much
moisture from gasbench gets into the source(?). Feng
"Harlow,
Benjamin"
<[log in to unmask] To
> [log in to unmask]
Sent by: Stable cc
Isotope
Geochemistry Subject
<ISOGEOCHEM@list Re: [ISOGEOCHEM] Electronics
.uvm.edu> trouble.
08/28/2008 11:13
AM
Please respond
to
Stable Isotope
Geochemistry
<ISOGEOCHEM@list
.uvm.edu>
Hi Penny,
It sounds like a short, maybe after the source is compressed or with the
penning somehow? Your source could be turning on and off from a short,
from the crossed wires or just being dirty. Also it could be from your
high vac reading. Since you said the vac ok light is turning on and off
that seems a likely first place to look.
Cleaning the penning is a time consuming and delicate task. You can get
a spare AIM kit just in case the tab on the anode got tweaked a little
bit during cleaning. And I'd double check for leaks before assuming a
board is bad. Also are all your backgrounds low?
The engineers are quite a bit of help too so it would be worth giving
them a call.
Good luck, Ben
Benjamin Harlow
Manager, Stable Isotope Core Laboratory
Washington State University
School of Biological Sciences
G-81 Eastlick
Pullman, WA 99164-4236
Office: 509-335-6161
Lab: 509-335-6154
Fax: 509-335-3184
Laboratory for Biotechnology and Bioanalysis (LBB2) Stable Isotope Core
http://www.isotopes.wsu.edu
-----Original Message-----
From: Stable Isotope Geochemistry [mailto:[log in to unmask]] On
Behalf Of Penny Higgins
Sent: Thursday, August 28, 2008 7:48 AM
To: [log in to unmask]
Subject: [ISOGEOCHEM] Electronics trouble.
Our Delta plus XP is giving me fits, and I've finally concluded that
it's an electronics thing. I suspect I'll be calling for an engineer
in the next day or so, but thought I'd try here first for help.
The symptoms are thus:
I'll be watching the instrument running along just fine. After about
5 or 6 analyses (we're running waters for d18O right now on the Gas
Bench), frequent spikes will appear. Every 20-30 seconds. Associated
with each spike is a faint click from the electronics of the source.
The source itself flicks on and off, then the vacuum ok light flicks
on and off, and in the end, the source shuts itself down, but the
turbos keep running. The vacuum still seems to be ok. Last week, I
replaced the filament (which looked fine), and cleaned the penning
gauge, thinking that these were the problems. I did discover a loose
wire in the source, which I fixed.
So my hypotheses are:
1) the loose wire in the source is back, causing a short which is
causing trouble (Though it only acts up when a sample is being
analyzed. It has no troubles if I run on-offs for hours. And
linearity has been excellent.)
2) something in the source electronics is fried - which is way beyond
my capability to fix.
Has anyone had similar troubles to this? Are there any other potential
causes?
Any help is surpremely appreciated.
Thanks,
~Penny
*******************************************************************
Dr. Pennilyn Higgins
Research Associate
"SIREAL"
Stable Isotope Ratios in the Environment Analytical Laboratory
Department of Earth and Environmental Sciences
University of Rochester
227 Hutchison Hall
Rochester, NY 14627
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Office: 209b Hutchison Hall Lab: 209 Hutchison Hall
Voice : (585) 275-0601 Outer lab: (585) 273-1405
FAX : (585) 244-5689 Inner lab: (585) 273-1397
http://www.earth.rochester.edu/SIREAL/index.html
*******************************************************************
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