[3dem] Shutter problems with Digital Micrograph ver 3.1

rubinst1 john.rubinstein at utoronto.ca
Thu Nov 24 10:05:11 PST 2016

Dear Colleagues,

We recently had Digital Micrograph on our Tecnai F20 (with a Gatan K2 Summit DDD and Orius CCD) upgraded from ver 2.3 to ver 3.1.
Since the upgrade we have had intermittent problems with the cameras not applying the microscope shutter/beam blanker when they should. When the shutter is not applied properly cryo-EM specimens are pre-exposed before images are acquired.

We are not exactly sure of the sequence of events that leads to the problem. However, once we notice there is a problem during a microscope session we can confirm that the camera isn’t applying the shutter properly because  (1) the voltage from the shutter cable is 0V (when it should be 5V to apply the shutter) and (2) the microscope gun deflector value correspond to no shutter being applied. Samir Benlekbir has worked out a sequence of steps (involving raising and lowering the microscope screen and starting and stopping the camera) that will correct the problem once it has been detected, but of course this shouldn’t be necessary.

Has anyone else had a similar problem caused by upgrading to Digital Micrograph 3.1? If you have, please let me know how you resolved it.

Thanks and best wishes,

John Rubinstein
Molecular Structure and Function Program
The Hospital for Sick Children Research Institute
686 Bay Street, Rm. 20-9705
Toronto, ON
M5G 0A4
Tel: (+001) 416-813-7255
Fax: (+001) 416-813-5022

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