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Look behind the back of the low-Z sample box. There is a rail along the back of the box attached to the stage plate. There are two allen hex bolts going through this rail to hold the back of the low-Z box to the rail. Use a 5/32" Allen wrench to loosen each bolt a few turns. This will allow the box to slide upstream and downstream on the stage.
Remove the clamp for the O-ring between the two gas sections.
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