[3DEM] Re: tecnai version 2.1.5
mike.lewis at Vanderbilt.Edu
Tue Jun 28 16:49:52 PDT 2005
We just had another vB short problem on our Polara (2.1.5, but probably unrelated to software). A partial short in the vB switch cut/reduced power to the board which reads all of the switches. The status of the MSC, insertion rod, column valve, etc switches became unreadable & they were locked out. The board didn't respond. It wasn't until after a new board was fitted that FEI traced the problem back to the vB switch.
We also had an intermittent short to the solenoid on the insertion rod. That was shored up by shrink wrapping a splint to the Oxford/Gatan cable & connector. This is the same connector set up & problem sometimes seen with the Oxford CT3500 holder controller cables, with very fine wires that flex & can get bent sharply at the connector.
From: owner-3dem at ncmir.ucsd.edu on behalf of Bob Grassucci
Sent: Tue 6/28/2005 3:32 PM
To: Angel M Paredes
Cc: tecnai at wadsworth.org; 3dem at ucsd.edu
Subject: [3DEM] Re: tecnai version 2.1.5
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I am very sorry to hear about your FEG tip. One thing that
surprises me about this event is that the user did not realize that Vb was
open since it is right next to Va. The sad thing about it is that even if
he did realize it the software would not allow him to close Vb since it
would be locked. I agree that the software should protect the tip at all
costs and close the column valves when venting the airlock. I know that if
I hit the cartridge button V7 and V4 do indeed close. We have been having
the opposite problem with venting the airlock that it fails to open the
vent valve at all unless we hit vent air lock more than one time. There is
no substitute for common sense when using these instruments that are still
on the "bleeding" edge. Whenever there is a potential for a vacuum
disaster the number one mantra I instill in the users is protect the tip
and close the column valves. If you have to leave the room close the
valves. When a tip goes bad there is at least a week of down time. My
hope is that you get a good stable tip as a replacement.
The integration of the TVIPS cameras leaves something to be
desired but we are slowly working through it. This is our main
"bug". Good luck with your tip replacement and I hope your are up and
running very soon.
At 01:39 PM 6/28/2005 -0500, Angel M Paredes wrote:
>Sunday we experienced a rather bad malfunction that people should be aware
>of that destroyed our FEG tip. On our Polara, the user working with the
>scope decided to remove the MSC to exchange the specimen. To do this you
>have to vent the airlock. He pushed the "vent airlock" button. Since he
>had not closed the column valves, the software I believe was supposed to
>have detected this and closed the column valves for him to protect the
>FEG. The software unfortunately did not. What the user did not know was
>that there was an electrical short in valve B that told the software that
>valve B was closed when it was in fact opened. Instead of telling him to
>close valve B as it should have done, the software detected that valve B
>was already closed and told the user instead to close valve A... which he
>did. The software then vented the airlock but with valve B opened instead
>of closed, the column was vented and since the software had not closed the
>column valves when the user pushed "vent airlock", the FEG was vented too.
>FEG tip gone.
>We are currently using version 2.1.5 of the user interface. Has anyone
>out there been experiencing any other bugs with 2.1.5? Thorsten had
>problems with his system rebooting when a log file was full and I went
>through the same thing during a bugcheck the system decided to perform.
>Another bug we've seen is in low dose. We use diffraction while in
>search. Every now and again the search mode goes from looking normal to
>looking really strange and becoming very difficult to align. When I go
>from diffraction back to regular image mode in search, I find that the
>microscope has gone from a magnification of 52,000x to 52x while in
>diffraction and this is the reason why the search mode goes from looking
>okay to looking strange. FEI's response is that we are not supposed to be
>using diffraction and experiments in the factory have shown that if one
>switches in and out of diffraction too quickly, it causes the mag to
>change. All I know is that version 2.1.3 did not have this problem. Are
>there any other problems I should be made aware of?
Howard Hughes Medical Institute
Empire State Plaza
Albany, NY 12201-0509
bobg at wadsworth.org
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