erict@flatline.UUCP (eric townsend) (02/17/88)
Problem: I live in an old, dusty house w/o central air or heat (eg: no filtering for the air). Add to that burning incense and stir frying of various plants and animals. Lots of dust. Huge amounts of dust. All this gets sucked through my 3b1. Dust collects on the floppy drive latch, etc. Generally nasty for everything involved. Solution (of a sort): Reverse the fan and add a easily removeable filter. We had a Northstar and a Motorola S8000 at my old job, and they both had filtered air blown through them. Why not 3b1's and PC's? My guess was the manus didn't think owners would remember to clean the filters once a week, or something like that... Anybody tried this (and know an easy way to do it including Radio Shack part #'s :-) ) / see any problems with doing this? -- Just say NO to skate harassment. | Just another journalist with too much If I wish really hard, will IBM go away forever? | computing power.. Girls play with toys. Real women skate. -- Powell Peralta ad J. Eric Townsend ->uunet!nuchat!flatline!erict smail:511Parker#2,Hstn,Tx,77007
c4s@rayssdb.ray.com (Charles A. Sefranek) (02/18/88)
In article <409@flatline.UUCP> erict@flatline.UUCP (eric townsend) writes: > >Problem: I live in an old, dusty house w/o central air or heat (eg: no >filtering for the air). ... > ... >Solution (of a sort): Reverse the fan and add a easily removeable filter. >We had a Northstar and a Motorola S8000 at my old job, and they both >had filtered air blown through them. Why not 3b1's and PC's? A lot of manufacturers design the air flow this way so the heat generated by the fan motor itself doesn't get injected into the equipment, adding to the cooling burden. Fans give off a surprising amount of heat ! >Anybody tried this (and know an easy way to do it including Radio >Shack part #'s :-) ) / see any problems with doing this? > ... It shouldn't be a problem. When I opened up my machine the *ONE* fan was just resting in place with some foam tape around it to cushion and (presumably) quiet it. Just flip the fan around ... -- (Cute signature currently under construction...) Charlie Sefranek c4s@rayssdb.RAY.COM {cbosgd,gatech,necntc,ukma}!rayssd!rayssdb!c4s -- -- Charlie Sefranek c4s@rayssdb.RAY.COM {cbosgd,gatech,necntc,ukma}!rayssd!rayssdb!c4s
rms@meccsd.MECC.MN.ORG (Roger M. Shimada) (02/19/88)
In article <409@flatline.UUCP> erict@flatline.UUCP (eric townsend) writes: > [ huge amounts of dust getting sucked into a 3B1. ] >Solution (of a sort): Reverse the fan and add a easily removeable filter. One day, I was looking through the air vents towards the bottom of my 3B1 and noticed dust bunnies. Decided it was time for cleaning. The motherboard was completely covered with dust. The disk drives sit above the motherboard, and the hard drive has a box-like covering, so they were mostly spared. By the way, the only air flowing in though the top housing is on the right side, under the monitor. (A few square inches of the "striped" area.) Right over some of the power supply circuitry. Unfortunately, I had forgotten which direction the fan was put in. Several minutes after I powered it on, I noticed the machine starting to get warm all over. Changed the fan direction and it's never been that warm since. Is dust a bad thing to a 3B1? (Most of the chips on the motherboard are soldered in, if this makes any difference). -- Roger M. Shimada ihnp4!meccts!rms rms@MECC.MN.ORG
motteler@umbc3.UMD.EDU (Howard E. Motteler) (02/19/88)
In article <409@flatline.UUCP>, erict@flatline.UUCP (eric townsend) writes: > > Problem: I live in an old, dusty house ... [much dust ommitted] > Solution (of a sort): Reverse the fan and add a easily removeable filter. > Anybody tried this (and know an easy way to do it including Radio > Shack part #'s :-) ) / see any problems with doing this? A scrap of pantyhose stretched and taped over an intake grill makes an adequate filter for coarser types of particles, cat hair, etc. I ran an old kaypro II with an added fan and this sort of filter for years. Every month or so you need to clean it off or just throw it away. The advantage is very little air resistance and cheapness. The disadvantage is that it doesn't stop the finer particles or smoke. (You can zap these with an ionizer, but don't set it too near your crt, or all those micron sized particles will migrate to your nice, positive screen.) I played around with reversing the fan in my 3b1. Just pop the fan(s) out and flip it (them) to face the other way, and tape your "filter" over the grille(s). The power supply will run quite cool with the fan breathing on it, but the front of the motherboard warms up a bit. I ran this way for a couple of weeks with no ill effects, but finally switched back. You get less overall cooling when you do this. Gas cools when it expands, and warms when it is compressed. In suction mode, air expands and cools when it is sucked through little holes into the box, while if you reverse the fan, you are compressing and warming air. This effect may not have been the sole cause of the exess warming of the mother board (warm air wants to rise, and you will be blowing it down, etc.), but reduced cooling was noticable. I changed back after I got tired of warm air blowing over my fingers. Howard Motteler
wtm@neoucom.UUCP (Bill Mayhew) (02/19/88)
The air flow of the 3b1's fan can be easily reversed by simply turning the fan end-over-end in its holder. There are a couple of disadvantages to using positive pressure cooling though. Namely, all the air is first blown across the power supply, thus sending a wave of heated air over the rest of the components. Positive pressure tends to have less even air flow inside the machine, thus causing hot spots. Adding a second fan per the original AT&T specifications when reversing the air flow direction would probably be a good idea. I think I'd stick with the original cooling scheme and just make a point of it to vacuum the inscence and stir-fried-animal-part dust out of the machine every six months or so. --Bill
robert@mcco.UUCP (Robert R. Andrews) (02/24/88)
In article <804@umbc3.UMD.EDU> motteler@umbc3.UMD.EDU (Howard E. Motteler) writes: >In article <409@flatline.UUCP>, erict@flatline.UUCP (eric townsend) writes: >> >> Problem: I live in an old, dusty house ... [much dust ommitted] >> Solution (of a sort): Reverse the fan and add a easily removeable filter. >> Anybody tried this (and know an easy way to do it including Radio >> Shack part #'s :-) ) / see any problems with doing this? > >A scrap of pantyhose stretched and taped over an intake grill makes an >adequate filter for coarser types of particles, cat hair, etc. I ran [stuff about pantyhose and reversed fans removed] >the mother board (warm air wants to rise, and you will be blowing it >down, etc.), but reduced cooling was noticable. I changed back >after I got tired of warm air blowing over my fingers. > > Howard Motteler I used to work on a system that the keyboard was integrated with the monitor and keyboard. A big graphics station. It had positive air pressure cooling. The biggest problem was the air coming out of the keyboard. Caused chapped hands and tearing in your eyes. We could only work at this system for about an hour before you had to go get some moisturizer and rest the eyes. Nothing as fun as typing with dry, cracked fingers. Finally solved by putting a separate negative pressure fan in the bottom of the keyboard. Some boards are designed so that the most heat sensitive parts are first cooled. Changing the air flow could mess this completely. Heat is a chips worst enemy. Static is second. I think it best to assume the designer had to think about that. But my experience only not the designers. Any comments AT&T? Robert Andrews