Power Supply burntout AGAIN 3rd time, what gives?

[martinwood333]

To the OP, please let us know how you get on! I'm curious to see what the actual cause of this is.

I haven't said anything to the contrary, you just can't read, or your just trolling me?

You get the basic concept heat rises?...

My £0.02.

To get all technical, convected heat rises. Radiated heat doesn't... and there is a difference. (That's how ceiling radiators work afterall, they don't rely on convectors at the back of them. Your typical wall radiator is far from a "radiator" in fact... it's around 80% convected heat).

There will be very little convected heat from PSU components, because, well, there aren't really any means of effective convection. When the fan kicks in, it provides a passive airflow through the PSU, bringing it's ambient air temp down, thus cooling the components, regardless of the orientation of the PSU to gravity.

At the end of the day, even when the fan is halted, there isn't enough heat generated to make a noticeable difference to your case's ambient temp (assuming you have decent chassis cooling).

Personally, I install my PSU fan-down, but that's purely to avoid those pesky fine particles of dust that get through the case filters from settling in the PSU. If PSU orientation really did matter, so much to the point it was causing failures, PSU manufacturers wouldn't allow them to be installed in such a way. (Such testing is done on these thing's far more than you'd think.)

 

[Sasahara]

I'm not going to get into a scientific debate, but was was wrong in my description of heat rising. Technically heat itself doesn't rise at all. As I'm sure you know when a gas gets hot it expands and there for lighter than the same cooler gas around which causes it to rise causing convection current. The method of heating has no relevance.

The process in this case is doing conduction, convection and radiation. I think the big heat sinks inside most decent PSUs makes for decent convection after heat is conducted to them.
Regardless of how the heat is transferred to the air, once it's in the air a convection current is being created.

The fan in the PSU is working partially against this effect rather than with it, if it face up.
Can you acknowledge that? (Which was my point)

My original post was just advice to put the fan face down if possible, I didn't say that was the problem, just advice for the future that costs nothing, but could increase the lifespan of the OPs or anyone else's PSU. Ambient case temps were not mentioned.

Dust build up was also core part of my post, the 3rd paragraph was a very important point. It was the reason I gave why a PSU could fail as dust build up could comprise the cooling ability of the PSU.

How is this incorrect?

If you have no dust then having a fan face up probably won't ever be a problem, but how many people have a dust free case?

I'm not sure what you mean by

When the fan kicks in, it provides a passive airflow

A passive airflow is what you get when the fan isn't running.

 

[Sasahara]

I am not trolling anyone. You are the one that started getting all agressive. Fine, whatever. The ops thread has been trashed enough. It's most likely not even the reason he has had these failures.

I'm pretty sure all I did was give reasonable advice to the OP in my first post.

You then suggested my advice was wrong, saying the PSU fan would act like a vacuum cleaner.

I rebutted this because the fans don't have enough suction to do that.

You then effectively repeated the same argument, adding in "No psu's these days exhaust into the case"

And.

"Just about every psu sold today sucks air in through the fan and exhausts it out the back. If you have one that exhausts through the fan into the case there is something wrong with it as the fan will be running in reverse.

Don't see why you don't understand this.
"

Which I when I asked you if you were trolling me as I didn't say once the fans were exhausting into the case? Not aggressively, honest.

What I said was. the fans were working against the rising hot air, rather than working with the rising hot air.