[comp.sys.next] Vacuum Cleaner -- Reversing the FAN?

izumi@violet.berkeley.edu (Izumi Ohzawa) (12/13/89)

In article <185@toaster.SFSU.EDU> eps@cs.sfsu.edu writes:
>In article <394@helens.Stanford.EDU>, mike@relgyro.stanford.edu
>> It seems that the drive slot sucks in dirt from
>> all over the room, and deposits it on the optical surface.

>I've heard that this is only a problem on earlier cubes; they
>reversed the fan direction in the later ones.

This won't help if one has an earlier cube.

Can we open the rear panel and simply reverse the fan, if our
cube is the older one?  Has anybody done this?

I think somebody asked this once before, but I havn't seen the
answer.

To make sure, if the air comes out from the rear panel, your
cube is an older one, and your optical may get a lot of dirt.
Correct?

Izumi Ohzawa, izumi@violet.berkeley.edu

jacob@gore.com (Jacob Gore) (12/13/89)

/ comp.sys.next / izumi@violet.berkeley.edu (Izumi Ohzawa) / Dec 12, 1989 /
> Can we open the rear panel and simply reverse the fan, if our
> cube is the older one?

I asked a NeXT service technician this question, and he said that this is
NOT recommended: in addition to the fan being reversed in the current cube,
there are also more ventilation holes on the bottom.  (By the way, having
the air sucked in from the bottom of the cube causes the same problem in
cubes that sit right on the floor.)

Jacob
--
Jacob Gore		Jacob@Gore.Com			boulder!gore!jacob

joe@mathcs.emory.edu (Joe Christy) (12/13/89)

In a bunch of previous articles, people write:
>>> It seems that the drive slot sucks in dirt from
>>> all over the room, and deposits it on the optical surface.
>
>>I've heard that this is only a problem on earlier cubes; they
>>reversed the fan direction in the later ones.
>
>This won't help if one has an earlier cube.
>
>Can we open the rear panel and simply reverse the fan, if our
>cube is the older one?  Has anybody done this?

After my second optical drive died, I had several conversations
about this with NeXT people both here and in California. They are aware
of air flow and several other problems with the robustness of the
optical drives. They told me not to reverse my fan now, as that
would probably precipitate some other problems, but that
shortly they would have a uniform retrofit to all existing cubes
which would correct all known OD problems. Like the replacement
of the early optical drives, this will be free. At present, they
said to be sure to keep the cube off the floor, and to keep the
surroundings clean. From my own experience, I would recommend
vacuuming the air slots on the back and bottom from time to time,
rather than blowing off the dust, which can be amazingly deep.
-- 
Joe Christy         | joe@mathcs.emory.edu      | Time flies like an
Emory University    | {decvax,gatech}!emory!joe | arrow, fruit flies
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