Re: Spinning Problems AMX-500
george furst (furst@ernst.chem.upenn.edu)
Thu, 6 Nov 1997 19:18:39 -0500
>Date: Thu, 6 Nov 1997 15:17:25 -0500
>To: "Glenn Facey" <gafacey@science.uottawa.ca>
>From: george furst <furst@ernst.chem.upenn.edu>
>Subject: Re: Spinning Problems AMX-500
>Cc:
>Bcc:
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>
>>Dear Members:
>>
>>I have been having problems recently on my AMX-500 (Oxford 500, 51
>>mm bore, standard Bruker shim set, standard sample transport
>>system) with sample spinning, samples falling into the probe
>>properly and large Q-modulation sidebands on an inverse probehead.
>>Initially I thought the problem was with the probe. This, however
>>is not the case. I now think that I must take out the spinner
>>assembly and clean it. This is done by loosening the three long
>>screws on top of the upper shim stack and removing the lower shim set
>>and spinning assembly. I am a bit nervous in doing this. Is there
>>any advice out there aside from the obvious screwdriver-suction
>>problem.
>>
>>Glenn Facey
>>
>>
>>Glenn A. Facey
>>NMR Facility Manager
>>University of Ottawa
>>mailto:gafacey@science.uottawa.ca
>>http://www.science.uottawa.ca/~nmr
>
>Hi Glenn:
>
> We have basically the ssame system here at Penn that you have.
>We find that the shim unit has to be cleaned about once a month. If you
>don't want to remove the shim unit. we have had some success with making a
>giant
>q-tip out of a wioden towel, removing the probe. wetting the q-tip with
>isopropanol and cleaning the dirt out. How,ever the symptoms you discribe
>soon more serious i.e. a cracked insert glass. I would check out the probe
>cracks in the quartz in glass will also cause bad sidebands. If you do
>have to remove the shims make sure you turn-off the the BSMS or BSN-18 as
>you can quench
>a cryoshim if they have lots of current on them.
> Good luck
> George
>
>
George T Furst;Ph.D.
Department of Chemistry
University of Pennsylvania
Philadelphia,Pa 19104-6323
phone: 215-898-3407
fax: 215-8985129
email: furst@ernst.chem.upenn.edu