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Hi Penny,
Happy New Year!
Pumps, how happy are the pumps, are they ageing on bearings? Both turbos and rotaries can produce bizarre and intermittent vibrations that may be rattling the head amps. A similar problem sent me round the houses till I rested a finger lightly on the head amp casing. Similarly any building vibrations? Similar symptoms and not till I kicked myself and the chair away from the PC table in dismay did I pick up a floor vibration. The lab was on a top floor and the A/C units in the roof were just rattling enough.

Beyond that it's a logging oscilloscope on all the supply voltages, a lot of multimeters may not respond as rapidly as needed, or find a graveyard, full moon etc.....

Sam

________________________________________
From: Stable Isotope Geochemistry <[log in to unmask]> on behalf of Higgins, Pennilyn <[log in to unmask]>
Sent: 17 March 2015 15:28
To: [log in to unmask]
Subject: Re: [ISOGEOCHEM] Power supply - Update and continued problems

Hi all,

Thanks everyone for your advice on our strange voltage fluctuations. We have now had the UPS serviced and I did give the source a quick clean. It had only been about 6 months, but we'd been working the instrument hard. It wasn't too awful in there, but cleaning wasn't unwarrented.

Alas, the problem remains. I do need to set myself up with a multimeter to observe if the fluctuations exist places other than in the source (i.e. the other outlets on the mass spectrometer or elsewhere in the lab).

I've posted some screenshots of what I'm observing on my blog at the link below. Maybe there are further suggestions? I've heard more than one person suggest feed-throughs on the source as a potential problem. Could that be it? (If so, does anyone have any instructions or insights on how to repair the feed-throughs?)

http://paleopix.com/blog/2015/03/17/technical-help-needed-irms-instrumental-quandry/

Thanks again,

~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

                   [log in to unmask]

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
*******************************************************************

________________________________________
From: Stable Isotope Geochemistry <[log in to unmask]> on behalf of Harlow, Benjamin <[log in to unmask]>
Sent: Friday, March 6, 2015 3:54 PM
To: [log in to unmask]
Subject: Re: [ISOGEOCHEM] Power supply - someting is wrong with the instrument

Hi Penny, We had had intermittent spikes that turned out to be arcing in the source, particularly at the ceramic feedthroughs.  When was the last time the source was cleaned? Another time when we had a very systematic fluctuation, it was solved by a hard reset or power cycling the IRMS.  A reboot of the computer won't give you the same effect as draining the power from the boards and repowering them.

I would check all the simple avenues first.

Good luck,

Ben


Benjamin Harlow
Manager, Stable Isotope Core Laboratory
Washington State University
School of Biological Sciences
367 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
https://urldefense.proofpoint.com/v2/url?u=http-3A__www.isotopes.wsu.edu&d=AwIDAg&c=kbmfwr1Yojg42sGEpaQh5ofMHBeTl9EI2eaqQZhHbOU&r=13t-5_RLEERmjc03IcaWTCKbCkKNHtUcdqFgEOHRzXU&m=olB7W8-CJW94ovK3DKQcEzEMPX7xQMCFfS-aan8SgX4&s=Q3xfyRXl44hITStDQYLnuA6XUILEPKLhcTabD3njxG0&e=


-----Original Message-----
From: Stable Isotope Geochemistry [mailto:[log in to unmask]] On Behalf Of Higgins, Pennilyn
Sent: Friday, March 06, 2015 12:31 PM
To: [log in to unmask]
Subject: Re: [ISOGEOCHEM] Power supply - someting is wrong with the instrument

Thanks all for your suggestions. I'll be getting a data logging multimeter and will check that out.

I did try rebooting the computer. That didn't work. (sad face)

I'm relatively certain it's a problem in our UPS/power conditioner. We had it serviced recently, so I think (hope) that it is still under warranty.

Cheers,

~Penny

________________________________________
From: Stable Isotope Geochemistry <[log in to unmask]> on behalf of gerard olack <[log in to unmask]>
Sent: Friday, March 6, 2015 2:56 PM
To: [log in to unmask]
Subject: Re: [ISOGEOCHEM] someting is wrong with the instrument

HI Penny,

Follow Tom's advice, but also check the ground to, well, a ground on another circuit.  A different instrument is our building was seeing a regular pulse in the noise--turned out it was a coffee maker, cycling on and off to keep the water warm and ready to use, and some interesting wiring of the building itself.

I presume the peripherals and all plugged into the mass spec itself.  If not, check the ground voltages between the two circuits.

take care,

gerry

On 3/6/2015 1:27 PM, Tom Millican wrote:
> I should clarify that you connect the leads (probes) of the voltage meter to the contacts on an outlet on the mass spec.
>
> On Fri, 6 Mar 2015 14:24:46 -0500
> Tom Millican <[log in to unmask]> wrote:
>
>> Hello Penny,
>> One way to tell if it're related to the power source is to use a volt-meter with data-logging. You can plug one right into one of the outlets available on the mass spec. You should see the same behavior on the voltage log.
>> If you then take the voltage logging device and plug into a power
>> source outside of the mass spec, you can determine more accurately
>> the source of the fluctuations based on whether you still see the
>> fluctuations or not. (The power supply should smooth out some, but
>> rarely all.) -Tom Millican
>> (Syracuse)
>>
>>
>>
>> On Fri, 6 Mar 2015 19:11:55 +0000
>> "Higgins, Pennilyn" <[log in to unmask]> wrote:
>>
>>> Hi all,
>>>
>>>
>>> I'm having what I suspect is an issue with the power supply. I intentionally defer all electrical issues to others with *much* more experience. (Electrical issues scare the daylights out of me.) Hence, I send this message.
>>>
>>>
>>> I'm seeing regular (sinusoidal) fluctuations in beam intensity. They come and go. They're small, but not inconsequential. Little jumps of 10-20 mV at approximately 1 second intervals. These are over broader, irrregular increases of around 50 volts that will last 30 seconds or more.
>>>
>>>
>>> I can send images of scans if you're interested.
>>>
>>>
>>> I suspect that our UPS-power conditioner has taken a dump.
>>>
>>>
>>> I would like to know your collective opinions. I could be wrong. Could this be this be a problem somewhere in the mass spectrometer's power supply?
>>>
>>>
>>> More importantly, if this behavior warrants a complete shut-down of the system, or if I should just cease analyses until the power supply is stable?
>>>
>>>
>>> Thanks, all, for your help!
>>>
>>>
>>> ~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
>>>
>>>                     [log in to unmask]
>>>
>>> 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
>>>
>>>
>>> https://urldefense.proofpoint.com/v1/url?u=http://www.earth.rocheste
>>> r.edu/SIREAL/index.html&k=EWEYHnIvm0nsSxnW5y9VIw%3D%3D%0A&r=%2Fd%2BQ
>>> cd6fj7GEkXzpWBZqFg%3D%3D%0A&m=4VmrE2wo7hiXODAyeRm8gL8EVt8I4rVhMw7TeO
>>> hEZqY%3D%0A&s=c4defc0056e73f75c02cbdf3f407b56a0d615de594392b4de0e3da
>>> 29acc135b0
>>> *******************************************************************
>>
>> --
>> Tom Millican <[log in to unmask]>
>