So one of my 140mm Silent Series R2 fans blade has came off, and because it was shaking violently, I cut one of, which makes a difference, but it is still shaking.
You could have balance it if you would have cut off the right 2 blades. If the blade that broke was 1 then if you count around you should have cut off 4 and 7 leaving 2 blades then a space all the way around. Now it isn't worth it. Get a new one.