I was wondering what would happen to a PSU if the fan would blow air inside instead outside the chassis. Most probably it's a bad idea but how much time would it take for a standard 400-500w unit to fail under these conditions. Has anyone tried this?
-
Guns don't solve problems. I'll take 12
-
Re: Has anyone tried to reverse a PSU fan?
You create an area in the case where air becomes trapped and is not vented. Air enters the front of the case and exits through the back. -
Re: Has anyone tried to reverse a PSU fan?
SSSSSSSSSSSSSSSSSSSHHHHHUUUUUSSSSH!
Don't tell the manufacturers that, they'll start getting ideas and then we will have to fix whatever idiotic obsolescent idea they put to use.Comment
-
Re: Has anyone tried to reverse a PSU fan?
I've done it because I needed to cool the CPU heatsink with incoming air flow from the PSU...
I junked the PC long before I would find out if it would cause failure,Comment
-
Re: Has anyone tried to reverse a PSU fan?
Why I ask this is because I would like to try different cooling methods. I'm thinking of reversing the PSU because its close to the CPU heatsink and I would put a 120mm fan on the front side of the case so it would take the air out but I'm not sure how much heat the PSU creates and am worried of actually cooking the CPU with warm air from the PSU instead cooling it or cooking the PSU.Guns don't solve problems. I'll take 12Comment
-
Re: Has anyone tried to reverse a PSU fan?
You would be blowing HOT air on the CPU.
All those watts you lose in the PSU due to efficiency turns into heat in the PSU.
.
Put the 120mm in the side of the case so it blows on the mobo and install a filter on it.
.
As long as you have more CFM blowing in than out the case will be slightly pressurized and that will keep the dust bunnies out of the optical drives, card readers, other ports, and nooks-crannies.
.Mann-Made Global Warming.
- We should be more concerned about the Intellectual Climate.
-
Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.
- Dr Seuss
-
You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
-
Comment
-
Re: Has anyone tried to reverse a PSU fan?
I think the original ATX spec had the power supply fan blowing in.Comment
-
Mann-Made Global Warming.
- We should be more concerned about the Intellectual Climate.
-
Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.
- Dr Seuss
-
You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
-
Comment
-
Re: Has anyone tried to reverse a PSU fan?
I heard of people flipping all the fans in the psu/case to deal with idiots who would insist on putting thier ashtray in front of the computer, as to avoid sucking in all of that nicotine and tar into the unit. anybody who has serviced a chain smoker's computer would know what i am talking about.sigpic
(Insert witty quote here)Comment
-
Re: Has anyone tried to reverse a PSU fan?
It will work. But it helps if you take a sheet metal nibbler and do a bit of case modding. If done correctly you can actually isolate the airflow going thru the PSU and give a separate case vent for hot air to exit.Comment
-
Re: Has anyone tried to reverse a PSU fan?
There are lots of ways to throw fans at a problem, but the typical/normal setup people use is the most efficient. You could change the airflow and add fans or increase fan RPM to make up for reduced efficiency.
The real question is, what cause do you have to do this? Changing something that works for everyone else would seem to suggest you have some kind of unusual situation. As others have already mentioned, pulling heat into the system instead of blowing it out is generally a worse configuration, but truth be told, some of today's modern cases have such an abundance of fan mounts and vent holes that if you simply put a fan everywhere there is a place for one it should run cool enough unless it's a high heat (gaming, extreme overclocking, etc) system or running during summer w/o air conditioning. One exception is OEM cases, often they have only the PSU exhaust and a case rear exhaust fan with a duct channeling air past the CPU heatsink. In this configuration neither of the two fans can be reversed without significantly compromising cooling as they are barely adequate at cooling in their original configuration.Comment
-
Re: Has anyone tried to reverse a PSU fan?
I have to laugh when I see people using scads of fans that don't do anything much because of how they used them.
Not counting the PSU fan if you have more than 2 fans and you're having issues then the issues are probably a poor design and lay-out.
A full tower case is something less than 2 cuft in volume.
Most cases are smaller.
With a 2 cuft volume a measly 60 cfm [of actual case flow] will change-out 100% of the air every 2 seconds.
That is more than enough.
Two 80mm fans can easily achieve that if they are sensibly installed.
Note: I said 'actual case flow'.
That doesn't have much to do with the cfm ratings of you fans.
Flow restrictions and short-cycles will make actual case flow and fan cfm ratings very different.
Fans sucking through filters or right in front of drive cages are going to create a lot less actual case flow than their cfm ratings suggest.
To get 60 cfm of -case flow- you may well need 100+ cfm of -fan flow- [rating] depending on the specifics and lay-out.
These new cases with fan holes all over the place can actually be detrimental to cooling if the fans and holes aren't well located.
Much of the air simply gets short-cycled.
Which means you actually have less flow -through- the case than you think you do.
That 50-60 cfm exhaust fan might well be only -changing- 10-20 cfm worth of case air if it has a bunch of holes next to it.
[Which is one reason I like case fans to blow -in-.]
If you are blowing air out and there are unfilled vents anywhere near it, then the air through the vent holes is right at the suction of the fan so it blows right back out and it never gets more than maybe an inch into the case.
- Such a fan arrangement isn't doing much for cooling.
These new cases with 4,6,8 places to put fans are really just a scheme to sell fans.
- If you have an over-vented case:
You should cover all unfilled vents anywhere near a fan and only leave those vents open that cause flow -through- the case.
-or-
Use one fan [with no open vents near it] that blows -in- directly onto the mobo and let natural cooling [heat rising] take care of the rest through all those holes. With a bazillion holes [some high and some low] and the one fan to 'stir it up' it WILL do it all by itself so you don't need more fans than the one [Not counting PSU fan.] which eliminates any low flow hot spots.
-or-
Don't buy cases with unneeded vents all over them in the first place.
[Which is getting hard to do...]
-
The arrangement I like best is filtered 80-100+ cfm fan[s] in a side panel with no other holes.
At least one fan should be right about over the mobo CPU&RAM area.
If the drives aren't well spaced put the other fan there.
I ~know~ the air is getting -in- resulting in case air exchange that way.
And that's enough turbulence to not sweat hot-spots.
[Exhaust fans usually don't prevent hot-spots.]..
Since most PSU fans are around 30-40 cfm and more is blowing -in-, the case is slightly pressurized with filtered air and all the other case holes [including air-leaky ports and optical drives] have filtered air blowing out, which keeps dust out of them.
- Overall that works on the hole riddled 'chicken wire' cases too - but you get less or no cleaning affect at the ports and drives because the differential pressure can't build. If you want to keep ports and drives clean with one of those cases then start covering vents until you have some flow through the ports.
- Using that plan, if you can put a wet finger over a crack and feel a little air blowing out then you got it right.
.Mann-Made Global Warming.
- We should be more concerned about the Intellectual Climate.
-
Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.
- Dr Seuss
-
You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
-
Comment
-
Hi friends
I have reverse engineered this tester, schematic is attached and is complete except for capacitor values. These testers annoyingly have no model number but they are the ones you find on the first page of just about any website if you type in "18650 4-channel tester". There is also a 2-channel variant and a newer 8-channel variant. They are very cheap (about £15) and can measure voltage, current, internal resistance and capacity. They have a multicolour display for all these statistics. They also have terminal blocks so that if you want to use a breakout board... -
Hi everyone, I recently acquired an HP EliteBook 840 G4 (6050A2854301-MB-A01) that I'm hoping to bring back to life. I'm fairly new to laptop repairs but eager to learn and willing to put in the effort to understand and fix this. Any advice or guidance would mean a lot!
What Happened
The issue started when the laptop was accidentally plugged in with reverse polarity. Before this incident, the laptop would show a power/charging light whenever it was plugged in. However, now it's completely unresponsive—no lights, no power, nothing. I've been doing some research and understand... -
Hi Folks
I need your help in a design problem. I have a power source that provide 3.3V, 5 V, +12V, and -12V. Each output is rated at 5A individually. Now i need to create a 4 way switch which will allow me to select the output I want. Unfortunately cannot find a 5 way rotary switch that can handle 5A. The ones i find are too big and used for main electricity board. Hence not suitable for my project.
So what i was thinking was to do the following
- Use normal 5 way rotary switch rated for 500mA.
- Connect the output of this to 4 channel 5V relay. So... -
Greetings i am in the process of reverse engineering the bios logic for the 8FC8 suffix so far I have found most of the bios functions related to the suffix from a bios dump and I have verified inputs and outputs to test with plus the chartable for the 8FC8 suffix. -
Hello everyone
I attach a schematic and teardown photos for the DoCreate DHJ567 handheld spot welder. I bought this welder for temporary use while my supercapacitor welder was waiting for replacement parts. It cost only £24, though there is a screenless version available for £17.
Performance: The absolute maximum it can handle appears to be 0.15mm of pure nickel. Reliability was not great - welds were very inconsistent, ranging from weak attachment to burning through the strip. However, I was able to build a 5S2P pack without losing any cells. It's a bit difficult getting...
Comment