Power Supply Fan Direction

[DiskChris]

I went ahead and had the local electronic repair shop throw in a new fan in my A2000 psu, as the old one was getting pretty loud and I'm not so good with a soldering gun. And instead of blowing air out, it now sucks air in, so I called and said I thought it was backwards and he said he did that on purpose because it's better to pull air in for cooling than blowing air out, and that it will increase the lifespan of the psu and the fan because you're not dragging hot air across it, and that all the modern psu's do that...

[QuikSanz]

That does not make sense. Why would you want to force all that heat onto your electronics? You really want to suck it all out of the computer as it is the only fan in the machine.

Chris

[DiskChris]

Right?? That's what I was thinking.

[paul1981]

I went ahead and had the local electronic repair shop throw in a new fan in my A2000 psu, as the old one was getting pretty loud and I'm not so good with a soldering gun. And instead of blowing air out, it now sucks air in, so I called and said I thought it was backwards and he said he did that on purpose because it's better to pull air in for cooling than blowing air out, and that it will increase the lifespan of the psu and the fan because you're not dragging hot air across it, and that all the modern psu's do that...

Bad thing about blowing air in is that it blows more dust in.
Good thing about blowing air in is that your computer should run a bit cooler.

I'm OCD about such things though and if the A2000 should blow air out then that's how I'd want it to remain.

If you like you can turn the fan around yourself maybe (depending how long the fan wires are). TBH, if the fan is soldered to the PCB I'd have put a fan plug socket on it so the fan can be easily replaced in the future.

[AmmoJammo]

PSU is most likely going to be the hottest part in the computer, so I'd be having it blowing air out the back of the case.

Either way will probably be ok, but as its also the highest vent in the case, having it blowing IN, isn't going to work so well when convection comes into play.

[James2002]

PSU is most likely going to be the hottest part in the computer, so I'd be having it blowing air out the back of the case.

Either way will probably be ok, but as its also the highest vent in the case, having it blowing IN, isn't going to work so well when convection comes into play.

Your right.  Electronics always will get very hot. The heat shortens electronic components over time.
 
 Other thoughts:
 Hand soldering should be easy to learn. There is a lot of tutorials on youtube how to do that.
 I don't understand why the guy didn't do it the way you wanted. Customer is always right.

[Oldsmobile_Mike]

It's backwards.  The A2000 is designed to pull in fresh air through the vents at the front of the case, across the cards, between the drives, and blow it out the back.  Replacing it doesn't require any soldering, in fact it can take a standard 80mm PC power supply fan.  Just unscrew and stick it in.  The connector is even identical, although the cord on PC PSU's is typically a lot longer than needed for inside the A2000 PSU.  Only caveat - the two wires on mine needed to be flipped, since I guess the "standard" was reversed, sometime between A2000 days and modern ATX specifications.  

Obviously you'll want to observe standard electronics precautions of not poking your screwdriver into anywhere it doesn't belong.  :roflmao:

[danbeaver]

When I replace PSU fans the wiring stays the same (remember than DC  electronics in not always reversible, OK they are rarely so), but there are usually four screws that mount the fan to the PSU box; unscrew these, flip the fan around, and replace the screws.  Its been awhile since I pulled an A2000, but I'm pretty sure its pretty darn easy (no soldering, just Phillips head screwdrivering).

I agree, the fan should pull air in from the nether regions and vent thru the PSU to the outside; failing that, liquid nitrogen makes a nice replacement. Just pour it on in a constant stream and your cooling worries should disappear!

[QuikSanz]

You can safely switch directions on a 2 wire (only), fan by swapping wires. Make sure the front is correct for direction.

[guest11527]

You can safely switch directions on a 2 wire (only), fan by swapping wires. Make sure the front is correct for direction.

Nope. Most of them are electronically commuted, i.e. by a small chip in the fan. The electronics requires the power supply exactly in the specified direction. The only way how to reverse a DC brushless fan is just to install it the other way around.

[amigadave]

What an idiot service tech!  The new PSU's that pull air in usually don't dump the hot air into the case, but direct it out of the PSU into free air.  Often a bottom intake with a rear exhaust, from the ones I have seen recently.

Do you want your Classic Amiga to last longer, or a replaceable PSU and fan?

[DiskChris]

While I agree fresh air intake is optimal, when you only have one fan in the system your first priority should be to exhaust the heat...otherwise it has nowhere to go and gets trapped...I went ahead and switched it around myself...first time opening a PSU and nobody got hurt:roflmao:

[F0LLETT]

All fans are marked (with arrows) to tell which way they rotate and which way the airflow is.

[Tenacious]

While I agree fresh air intake is optimal, when you only have one fan in the system your first priority should be to exhaust the heat...otherwise it has nowhere to go and gets trapped...I went ahead and switched it around myself...first time opening a PSU and nobody got hurt:roflmao:

+1.  If I'm trying to make a machine last, I add more small fans to blow on the the hot stuff and stir the air.  Then I feel better about using the PS fan to inflate the case.  

The real benefit of reversing the PS fan is controlling dust that is normally drawn in thru the floppy drives, etc.  After the PS fan is turned to blow in, an air filter should be added to the back intake.  It is then a simple matter to clean the air filter periodically (much easier and safer than cleaning out a floppy drive).

Compared to modern CPUs and graphic chips, near stock Amigas don't generate near as much heat.

[amigadave]

+1.  If I'm trying to make a machine last, I add more small fans to blow on the the hot stuff and stir the air.  Then I feel better about using the PS fan to inflate the case.  

The real benefit of reversing the PS fan is controlling dust that is normally drawn in thru the floppy drives, etc.  After the PS fan is turned to blow in, an air filter should be added to the back intake.  It is then a simple matter to clean the air filter periodically (much easier and safer than cleaning out a floppy drive).

Compared to modern CPUs and graphic chips, near stock Amigas don't generate near as much heat.

I think you misunderstood what the OP wrote, as he has reversed the fan to "exhaust" the heat, or blow outward into the room, not into the case.

I would not want the heat generated by the PSU to be blown into any of my computers, so would not do as you suggested by reversing the fan to blow through the PSU "into" the case and placing a filter material over the air intake at the back of the PSU.  I would always add at least one additional fan to blow air into the case and across any heat generating components, with an appropriate filter to keep out unwanted dust as much as possible. This would also compensate for the air being exhausted by the PSU fan, so little or no air would be drawn in through the floppy drive openings, and reduce the amount of dust drawn into the case from anywhere by the PSU fan sucking air out of the case.