[3dem] Cryoplunge 3 question

Edward J Brignole brignole at mit.edu
Thu Feb 7 07:04:33 PST 2019


I have seen this sticking behavior with our CP3. Our blotting pistons are semi-cylinders and if these pistons are slightly rotated in their semi-cylindrical track, the edges stick along the track and the pads extend slowly or after a short delay. Usually it helps to give the pads a few gentle tugs to seat the piston in its track.

Here’s a video of the behavior we see:

The slow motion movie is set for a 1 second blot, you hear a knocking sound when the start button is pressed, followed by roughly 0.5 second delay before the blotter extends.

Possibly some WD40 would be useful, do others lube their blotters? The manual also refers to an internal pressure regulator that can be accessed by opening the back of the CP3 - have others tweaked their blotter by adjusting this setting?

I have used two older CP3 models that did not have the screw to change blot force and these models have cylindrical blotting pistons that always extended smoothly. I borrowed a pair of these older style blotters to try in our CP3 and while they can be inserted, the pads do not extend - so it seems you cannot simply revert to the older model blotters. This is a bummer, since on these earlier models the blotter plugs also click nicely into place whereas in the model with the screws that alter blot force, the plugs do not give a clear click making it less obvious when rotating the blotter to the position where the N2 pressure can force the piston to extend.

Another issue I wonder if others have encountered, our CP3 tweezers fit in our model and do not fit in other CP3 models and vice versa. Seems the width and thickness of the slot in the plunging rod for inserting the tweezers was changed. Additionally tweezers seem to have variable width and thickness and some tweezers although clicked securely into the plunging rod are not rigidly held in place.

More info than you asked but I hope it is helpful and to know if others have noticed similar.

Thanks for bringing it up.


Ed Brignole, PhD
Cryo-EM Center at MIT.nano, 12-0174
Department of Biology, 68-583
Massachusetts Institute of Technology
brignole at mit.edu<mailto:brignole at mit.edu>

On Feb 7, 2019, at 08:02, Matthias Wolf <matthias.wolf at oist.jp<mailto:matthias.wolf at oist.jp>> wrote:

Hi David,

we also have a CP3 and I have never seen this problem.
I would check that there is sufficient N2 pressure. The mechanism is pneumatic. At low pressure it can get stuck or not move all the way. You could try to increase the gas pressure at your N2 cylinder regulator and check for any leaks at the fittings.

Best regards,
From: 3dem <3dem-bounces at ncmir.ucsd.edu<mailto:3dem-bounces at ncmir.ucsd.edu>> on behalf of Morgan, David Gene <dagmorga at indiana.edu<mailto:dagmorga at indiana.edu>>
Sent: Thursday, February 7, 2019 7:01 AM
To: 3dem at ncmir.ucsd.edu<mailto:3dem at ncmir.ucsd.edu>
Subject: [3dem] Cryoplunge 3 question


    We are currently demo'ing a Gatan Cryoplunge 3 (CP3) freezing robot.  From time to time (and randomly as far as we can tell), there is a significant delay between the time the start button is pushed and when the blotters actually close.  Since the countdown for blotting time starts when the button is pushed, the delay causes the actual blot time for that particular grid to be too short.  Does anyone else who has a CP3 see this issue, and if so, is there anything that can be done about it?  Thanks in advance.

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            David Gene Morgan
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             IU Bloomington
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