NOTE: I wish I had taken photos during this process, it would help explain things more easily. Unfortunately, it didn't occur to me to do so until I was already finished reassembling everything. I will be disassembling the system again soon for The AlienMaster Project and will take some photos to help make this all more clear.
One of my favorite features of my Area-51 system are the case's louvered, motorized top vents. Unfortunately, ever since my system arrived in September 2010 the top vents would screech and squeal when opening and closing, and the opening and closing motion was jerky. This past week while cleaning dust from the fan assembly I decided to investigate the cause of the loud vents. Here is what I found.
After disassembling the vent assembly, I examined the mechanism which controls the opening and closing of the vents. A small motor is used to move a slide forward and backwards through a channel in the top left side of the vent assembly. This slide is attached to the frame with 3 screws that pass through slots in the left side of the frame and attach to posts in the side of the slide and allow the slide to move back and forth while limiting its range.
Attached to this slide were 5 small pads similar to computer mouse feet or "skates." These pads were woefully attached. It appears that the "gloop" that was used to secure the pads was basically useless, as all of the pads had dislodged and moved about. The pads were still sticking to the slide, but they were no longer sticking to the spots they were intended to, which are marked by an outline which has been stamped into the metal itself. Having moved about as the arm operated, the pads created trails of sticky adhesive on the slide and within the channel that the slide sits. This glop had attracted all sorts of dust and dirt, and seemed to be "gumming up" the operation of the arm.
So, the first order of business was to remove these pads and clean the slop up. Ten minutes with some Goo-Gone and everything was clean. Next I attempted to "dry fit" the slide back into the channel without any pads. This revealed a second source of screeching from the slide: The mounts which attach the slide to the frame. These are a bit difficult to describe, but basically the slide has 3 posts which protrude from its side and pass through 3 slots in the left side of the frame. A screw attaches to the end of these posts to mount the slide to the frame. Unfortunately, these posts grind along the top and bottom of the slots that they pass through. I used a Dremel tool to grind down the top and bottom of these posts slightly, providing them a bit of separation from the channels that they passed through.
After another "dry fit" I found that the slide moved very easily and there was much less grindy noise. I set about deciding what to use to replace the original pads. The answer was pretty obvious: a spare set of mouse feet or "skates" were my answer. I had a spare set of mouse feet already about, so I cut them down and attached the pieces to several locations along the slide. These are the particular feet I used, but. the important information is that they are made a low-friction material that is .6MM thick. The adhesive on these feet is very secure. Short of purchasing a sheet of the material from which the mouse feet were made, they seemed like the perfect solution.
I reassembled the vent assembly and reinstalled it onto the top of the case.
The moment of truth: My vent assembly is now totally silent and opens and closes smoothly, and has been for the last several days.
Hopefully this will help if you find that your are having the same troubles with your Area-51's vents as I was.
I will try to post some pictures within the next week when I have the vent assembly taken apart for my next project.