Umax 2200

My Umax 2200 scanner seems to be dragging on the glass from the inside. Does anyone have alignment instructions to get this set up right again? It's a SCSI scanner, which you can't buy anymore (except for $1000) and my computer (1995 version) does not accept a usb card-- I've tried. So I have to get the Umax working. I need mechanical alignment instructions, and distances. I have a dial caliper that I can use to set the mechanical distances, etc. (I hope.) Thanx all. --doug