ATX power supply upside down?

Of course, but naturally you must turn the monitor and keyboard upside down too.

And it will run a bit slower, because some of the electricity will dribble out of the holes. Makes the Chinese people a bit angry.

Ken

Yes they can....the electrons won't fall out :)

electronic components heat up. if you place PCB upside down heat will go into the base of resistors and transistors, etc.. so I wanted to know if that would be a problem.. a simple 'yes' or 'no' would do.

There is not an absolute answer. Some (most? all?) ATX supplies won't care; I'd guess that most (all?) that are cooled with a fan would be the "don't care" type. If the power supply did have restrictions on its orientation, the manual should so state.

Just make sure that there is a lot of air from the fan to blow through it. Technically it is best to run it in the position where the heat will rise off of the circuit boards, and not back to the circuit boards.

On 30 Jul 2005 16:03:48 -0700, "orange" put finger to keyboard and composed:

I understand your concern. I have a 350W Antec whose normal mounting arrangement has the PCB upside down. In addition to the obvious heating issues, there is an intake fan at the bottom of the case which blows additional heat from the nearby CPU through the PSU and out via the exhaust fan. Not an advisable setup IMHO.

- Franc Zabkar

The power supply fan is part of the case cooling system; it's not just to cool the PS (if it were, the intake would be outside the case).

In that case, upside down would be better since the PCB is mounted on the top of most ATX power supplies. Andy Cuffe

snipped-for-privacy@psu.edu

You'll be fine either way, some PC's mount the supply upside down anyway. The cooling is all done by the fan so convection is not an issue.

Most of the thermal energy genereated by losses in a component will sink in a pcb. Due to conduction in the leads. And most powersupplies are cooled with a fan so there should be a problem.

As others have said, electrically there's no problem. Thermally it should be OK, just make sure of where all the venting is and that it won't be blocked - this is probably fine since you'll have the PC board on the top, against the case, and there's likely no airflow intended under the board in any case.

My concern, though, is mechanical. My experience with ATX supplies is that the build quality is unbelievably cheap (not as in inexpensive, but as in junk). In my wife's office I've had to replace

But to the point, power supplies have heavy stuff like heatsinks and transformers mounted in various ways to the PCB. Bolted stuff is OK, soldered is problematic. There's vibration from the cooling fan, plus high-frequency stuff from electrostrictive effects. I'd be worried about long-term fatigue of solder joints when the vibration is combined with gravity's unrelenting tug.

I've never seen one fail when installed upside-down, nor have I installed one this way, this is more a theoretical concern than anything else. Given the choice, I'd install it with the PCB on the bottom assuming the orientation of the PC's case allows this.

Steve

In most cases, that would mean mounting it either upside-down or on its side, since the boards are typically not on the bottom of the power supply.

Hi!

I've never had a problem turning a computer power supply upside down...the units I've used are often free of a case and put in any direction that will fit. Fan cooled units should not be bothered by direction or orientation of mounting. Just don't block the fan or inlet vents.

Convection cooled units may be a bit more sensitive to orientation and mounting direction...the wrong way could put the heat on the circuit board and components. Depending upon how hot the supply runs this may or may not be an issue. Of course you could always add a fan to these units.

William

On Sun, 31 Jul 2005 05:20:14 GMT, CJT put finger to keyboard and composed:

A typical ATX case cooling system has case fans. These fans should exhaust waste heat from the CPU, not the PSU.

- Franc Zabkar

They both do.

On Mon, 01 Aug 2005 00:03:16 GMT, CJT put finger to keyboard and composed:

Just to be sure we are talking about the same thing, when I wrote that "there is an intake fan at the bottom of the case" I meant that the Antec *PSU* has a second fan at the bottom of the *PSU* case. My Athlon XP 2500 CPU sits within about 5cm of this fan, and directly below it.

- Franc Zabkar

Well, sort of - but you have to vacuum them up from the bottom of the case every couple of months or so - otherwise you get a huge build up of voltage that can zap your fingers

David

J> Yes they can....the electrons won't fall out :)