Ventilation mods

A stock CC is fairly loud due to its noisy fan that draws the heat out of the case. The fan is held on a metal assembly by two screws that go into rubber bushings. The bushings are the only vibration isolation. This imperfection transfers the fan’s vibrations to the computer’s case that acts just like a loudspeaker membrane and radiates the noise.

from left to right: fan assembly with black rubber bushings and white velcro pads,
Papst fan with velcro pad counterparts, stock srews (now suprafluid)

There are three options to improve the situation:

1) A better fan that generates less noise.

The stock fan measures 80 x 80 x 25 mm. This a standard part. To replace it I chose one of the legendary Papst fans (here: type 8412 NGL) with a noise level of only 12 db(A) @ 1,500 rpm! Power consumption is only 0,046 W @ 12 VDC. The drawback is that airflow is ca. 30 % less than the stock part. So observe component temperature if your are going to stuff more stuff into your CC.

2) Better vibration isolation between fan and the case

I replaced the stock screws (top-right in the picture) with self-adhesive Velcro pads. Later I decided to remove the rubber bushings too (left in the metal assembly) and set the fan on four Velcro pads. For me, the result is overwhelming! I suspect that  the harddrive is now the loudest component in my DeepClassic.

3) Entire re-design of the ventilation. Okay, here things start to get a little sophisticated :)

  • First, one could reverse the direction of the airflow, place a filter in front of the fan (outside) and draw fresh air _into_ the CC.
    • advantage: keeps the guts of your CC clean
    • Check if all components get enough fresh air (logic board in separate chamber)!
  • Drill holes in to the top of the case to support natural convection of warm air as with standard CRT monitors. Makes only sense with reversed air flow! Think at least twice before trying this!!!
    • advantage: make use of natural convection
    • disadvantage: a) damages the beautiful case (depends on personal taste), b) cannot be reverted, c) could short-circuit the air flow inside the case and lead to overheating of certain components
  • Add a tiny 25 x 25 mm fan in the logic board chamber vertically to drive fresh air accross the board. Fan should be fixed onto the board and powered by some feeding point on the board itself.
    • drawbacks: a) another source of noise, b) small fans usually run at higher rpms an are noisy by nature.
  • Shift the fan to the top of the case above the CRT neck and drill holes into the case, of course.
    • advantage: frees the original space for upgrade components (top-opening CD/DVD-ROM drive?)
    • drawback: raping the case, as above mentioned

As of February 2003 I performed steps 1 and 2.