16-11-2003 13:09									#1
	Just noticed something odd about my power supply. Increase Your PM Length

I've had this system for over three years, and I just noticed this.

The power supply's fan is blowing into the box, not out. I thought they were supposed to always blow out.

Am I confused, did this change sometime during the past decade, or has this computer been running with a reversed-polarity fan for nearly four years?

It's a PIII 450 mid-tower with a 500 watt supply, and the supply is positioned almost right over the chip (which has it's own fan and huge heat sink), so the majority of the air flow is going across it. The air coming out of the supply isn't exactly cool, but it's not really warm, either.

The labeling on the supply, in its present location, is upside down.

	16-11-2003 13:16									#2
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The fan should blow out.

What the heck are you doing with a 500W power supply? Or rather, is it really a 500W power supply?

BTW, how many fans does the power supply have and how are they facing?

	16-11-2003 13:51									#3
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It's hard to put a power supply upside down, if you look at it, the bolts are NOT laid out symetrically. They do normally blow out. Maybe somebody installed the fan in backwards. You could unplug and then pull the power supply and open it, voiding any warranties remaining. Carefully, because while it's unplugged, it still has capacitors and can shock you, just remove the mounting screws and reverse the fan, replacing the mounting screws. But if you aren't having any problems, then don't fix it is my motto.

	16-11-2003 13:53									#4
	Got spare money?

The PS fan should definitely blow out--for obvious reasons--but older PSes' blew in, I assume because that way you were guaranteed a draft over the processor heatsink.

SP

	16-11-2003 13:58									#5
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Thank the geniuses at Intel. That was their original ATX spec. It should have another fan blowing hot air into the system from the bottom of the PS. Yes, that's right, blowing hot air into the system.

	16-11-2003 14:00									#6
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I wouldn't think it would be the end of the world if it blew in. You would still get air circulation. Just maybe not as good.

The biggest reason for the fan not to blow in is because of dust. Without a filter you will bring in tons of dust.

For people overclocking their computers they should have fans blowing in and out. For fans blowing in, they recommend you use filters to prevent too much dust from getting inside your case.

But dust isn't the end of the world. I live in the desert. And I never dust my house . The inside of my computer will just build up massive amounts of dust. I try to blow some out, but usually not that often. I even accumulate large dust balls inside my computer

edit: oh I thought you meant a case fan, not a power supply fan . Well in any case, if your chip hasn't burned up yet- you should be okay .

	16-11-2003 14:02									#7
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I think I have a few dead rodents inside mine. Maybe even a small dog.

	16-11-2003 14:03									#8
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Some ATX power supplies do have a fan right over top of the CPU blowing down, but not all of them do. In fact, only the expensive units have them.

	16-11-2003 14:06									#9
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I got the wattage by multiplying the input voltage (100-125) and amperage (5) listed on the label. Google listings say it's actually 145 watts.

It's a LITEON PS-5151-6B. It just has the one fan that I can see.

Since it has been doing fine for so many years, I don't see me changing it -- I am wondering if this could do with the two hard drive failures and one CDROM failure I've had during that time.

edit: dammit, the 145 watts is on the label, I just didn't see it. Bah.

	16-11-2003 14:09									#10
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quote: Originally posted by notyoueither Thank the geniuses at Intel. That was their original ATX spec. It should have another fan blowing hot air into the system from the bottom of the PS. Yes, that's right, blowing hot air into the system.

That bottom fan is the one I'm noticing. If there's a second fan behind the vent in the back, it's not apparent.

Of course, it's not in a good position for me to see it.

	16-11-2003 14:09									#11
	Increase Your PM Length

145W?

Run to your nearest hardware store and get yourself at least a 250W power supply.

	16-11-2003 14:10									#12
	Support Apolyton, buy Call to Power 2

The original Intel spec did not last too long, for obvious reasons. First they stopped putting two fans in, and then some bright light got the idea of venting the hot air out of the system. Like they used to do. It was a breakthrough.

	16-11-2003 14:16									#13
	Tired of ads?

The inside of the case is extremely dusty -- I thought it was just because I don't dust much, either.

Perhaps I should put some gauze over the PS vent?

	16-11-2003 14:18									#14
	Full PM-box? Change here!

No.

Buy a new power supply. If you get a 350W or 400W, you can use that in your next computer, too.

	16-11-2003 14:19									#15
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I have a couple of open slots in the back of my comptuer where I used to have cards and such. dust gets into my case either way

	16-11-2003 14:20									#16
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If it's not broken, don't fix it.

	16-11-2003 14:22									#17
	Full PM-box? Change here!

yes, but eventually he will need a better power supply.

It's your choice. Now or later. Just remember if you upgrade your motherboard/CPU, to upgrade your power supply and fans as well.

	16-11-2003 14:32									#18
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Looks like it's broken though, the HDD failures and the CD-ROM drive failure were probably caused by an unstable power supply.

	16-11-2003 14:39									#19
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Hmm...maybe I should get one, then.

Another thing to add to my list.

Need a new UPS, too. The electronics in the old one got fried somehow a while back.

	16-11-2003 14:41									#20
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If your area gets lots of lightning storms or blackouts, UPS is a good idea. Otherwise it's probably just optional.

	16-11-2003 14:43									#21
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They got killed by the crap power the power company is feeding your PC. That is their job. They take the bullet for your PC.

Salute as you bury that soldier.

	16-11-2003 14:44									#22
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quote: Originally posted by Urban Ranger If your area gets lots of lightning storms or blackouts, UPS is a good idea. Otherwise it's probably just optional.

UPS are never optional if you want your computer to live a long and healthy life.

	16-11-2003 14:45									#23
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quote: Originally posted by Urban Ranger If your area gets lots of lightning storms or blackouts, UPS is a good idea. Otherwise it's probably just optional.

I got worse -- a 30 unit apartment building with antiquated wiring and a bank of heavy-duty coin-op washers and dryers in the basement.

	16-11-2003 14:49									#24
	Got spare money?

Sometimes it's cheaper to get an entire case instead of just a new power supply, though less common with a tower. Try ComputerGeeks, or Pricewatch. However, I've lost two hard drives to a cheap power supply, so this is a place I'd recommend spending a little cash. Go over to Sharkey's extreme, and see what they're using in their current setups .

	16-11-2003 14:50									#25
	Inflate your Upload Space

I gave my mom a computer. It dies, and it was my fault. I had a tech fix it, had to replace the mother board. It dies again, and it was my fault again. I had a tech fix it, had to replace the power supply.

Gave it back to her again, along with a UPS. Immediately the site wiring fault light came on. Turns out none of the outlets in the house were grounded.

Hehe.

	16-11-2003 14:55									#26
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I had to install a grounded outlet in my first apartment here, as none of the existing outlets were.

Let me tell you, it's fun playing with a circuit tester and live AC, looking for anything that could work as a ground.

	16-11-2003 14:56									#27
	Support Apolyton, buy Call to Power 2

my red alarm light is always on for my surge protector.

I say **** it.

My mom's house is 1940's era. It has no ground lugs I have to use an adaport to conver the 3 prongs to 2. And the ground (loop) isn't actually grounded . But that computer is a P133. No big loss if that goes.

	16-11-2003 14:58									#28
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Another discount site I've used, but not for power supplies.

http://www.computersurplusoutlet.com/showproduct.asp?category=18&subcategory=85

They've got some apparently good bargains, but again I'm not sure if bargain is the best move with power supplies.

	16-11-2003 15:13									#29
	Increase Your PM Length

As an aside, everything OEM in this computer points to it being manufactured in early 1999, by Packard Bell, though it shows NEC on the front plate.

I remember buying it for $1000 mid to late '99 (maybe early '00), and thinking it a bargain at the time. Had I seen "Packard Bell" anywhere on the display, I wouldn't have purchased it, but it's been a good box all this time.

	16-11-2003 15:35									#30
	Increase the size of your Attachments

My computer has three fans: one sucking air in and two blowing out (one dedicated to the power supply). Case has airholes on both sides of the tower, allowing additional airflow. I don't recall the age of the tower, but it has housed a couple of motherboards over the years.

All in the name of keeping it from overheating.