PSU Modding Threads

PSUs: The source of DC power for all components in the PC & often a big noise source.

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PSU Modding Threads

Post by MikeC » Sun Jun 06, 2004 11:52 am

Merge Sticky: How to completely drain a power supply...
Safety issues for PSu modders

Sticky: Building a PSU intake duct/vent
To get it cooler air so the thermally-controlled fna does not ramp up.

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Post by Bluefront » Tue Jun 08, 2004 3:48 pm

Well here's my Fortron mod, which opens up the inside of the PSU slightly for much better airflow. You might have a clearance problem with this mod, depending on your particular MB and CPU heatsink. But if it'll fit you'll get a less restricted airflow path through the PSU.....quieter and cooler.

Link to original thread on this mod.

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Post by Bluefront » Mon Jul 12, 2004 8:23 am

Here's my second Fortron mod. Any PSU with a bottom facing fan could be used. This particular mod could be combined with the mod in the previous post.

There are several advantages to this setup. It moves the PSU further inside the case which lessens the noise of the fan, adds a padded duct to the psu for the same purpose, and improves the airflow path to the PSU. You could also completely remove the rear PSU grill for even better airflow.

Link to original thread on this mod

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Post by orionlion82 » Mon Jul 12, 2004 6:16 pm

i got one for yall - its a good one (everyone exists in their own context, so...)
i have a 500W PSU that is not doing the job. its cheap junk, and like 98% of the time, $ goes elsewhere.
i am aware that instead of buying a nice expensive power supply that will do it all, it is possible to get away with dual power supplys, either keep the 500w pos and get a nice 250 to share some load, OR
use that old windows 95 era 200W dell power supply i have in the basement. i tried shorting it to get it to turn on as you would a P4 PSU, but nothing happens when i short it, and i verified that im doing it correctly on the 500W... that old dell PSU has an ATX connecter, a handful of molex, but the secondary MOBO plug is NOT a square 4 pin 12v like we have today. it looke (roughly) like the SATA power connectors (rectangular head, 6 wires) and BTW no green wires at all.
if i got that thing running i know i would have a decent mid quality PSU at 200 watts i can pop a few molex onto, dig up a spare switch , and i could save much needed $$ with a DIY and some spare parts (gotta love 'em)
any suggestions from the PSU MODDers? i dont want to arbitrairly short it out, or re solder a fuse or something...

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Post by maxw » Wed Aug 25, 2004 12:57 am

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Post by MainframeGuy » Fri Sep 10, 2004 6:07 am

I have found this elsewhere which I am sure people here are all aware of as a possibility, the 5v / 7v fan trick bot for a PSU.

Just thought I would post link incase it is useful to someone in this thread.

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Post by Solid Snake » Mon Mar 21, 2005 3:14 pm

This is my truly slient mod. The PSU no longer has any moving parts. Here is the thread:

Update: I've been using this PSU for about a month now with my overclocked 1533 @ 1616 Athlon XP system which contains a GF2MX, TV Tuner card, SB Live!, 2 HDD's and a DVD+CDRW combo drive. The PSU also runs a 3' long neon light in my bedroom, my cell phone charger and an indoor/outdoor automotive thermometer. The heatsink is warm to the touch, I'm guessing it's about 115 degrees F. Check the link at the bottom of the thread page, it shows the modding process.

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Post by Aleksi » Sat Apr 02, 2005 2:25 am

I wanted to write this post and gather up some information scattered on the forums and add some of my own thoughts. I'm hoping it will be helpful to people thinking about modding their PSUs, maybe even not for the first time. If you feel something should be changed, please feel free to post.

PSU modders: Read the posts behind the links in this thread, read this post and if you still have questions, use the search and if still unclear, ask.

Keep in mind, modding the PSU (and sometimes just opening) voids the warranty and if plugged to electricity, the PSU has lethal voltages inside, even for some time after removing the AC cord!

Here’s a quote from Dorothy Bradbury:

- PC PSUs are Switched Mode Power Supplies
- As such they include capacitors which hold a charge at high voltage
- ATX specification requires such charge is discharged quickly
---- however not all PSUs are to spec - parts may be omitted
---- specifically high-wattage ceramic discharge resistors (a cost)
- So disconnect the power from the PSU & leave alone overnight
---- that should ensure capacitors have discharged

And another quote by sthayashi:

Capacitors can hold their charge for a VERY long time if there's nothing there to drain them. My solution. Turn off your computer. Unplug the AC cord. Then attempt to turn on your computer, still unplugged. It may attempt to start up once or twice, but after that, it's usually done with and there'll be very little energy left within the PSU.

OK, so your PSU is too noisy? Why?

Does the fan(s) have bearing noise or clicking, but you feel it's otherwise OK? The fan airflow noise isn't bothering you?
The easiest one. Open the PSU and look up the datasheet on your fan(s). Next thing is to find a fan that matches the airflow of the original fan. Below are some (European) options. These are just for reference. The world is full of good fans; Globes, Yate Loons, Panaflos, NMBs, Noiseblockers(?). Check the recommended fan list for a suitable fan that you can find locally.

Papst 4412F/2GL (~55CFM)
120mm Acoustifan (49.5 CFM with and - 66.7CFM without the inline resistor).
120mm Nexus (36.87CFM)
Glacialtech 120mm Silentblade (37 CFM).

Panaflo (MMM) 92-L1A (43CFM)
Nexus 92mm (27CFM)

Panaflo (MMM) 80-L1A – 25CFM
Panaflo (MMM) 80-M1A – 32CFM
Nexus 80mm (20.2CFM)

The original fan(s) is connected to the PSU PCB either by soldered wires or a 2/3 pin connector. If soldered, take out the old fan's wires and solder the new ones in place. Be sure to solder them the correct way! It's too much hassle to to re-open the PSU and start reversing the wires just because you were in too much of a hurry to check which way to go. If the fan is connected with a connector of some sort, you have two options. Try to look for connector counterpart or remove the connector and solder the wires in place. That should be it.

Is the fan(s) running at low voltage, but you feel it's pushing too much air, so that it bothers you?

Look at the above. Same applies here.

Keep in mind though, that if the title is the case, then the PSU may have powerful fan for a good reason, maybe because the unit is capable of >400W power? Think about your options; You may have a light enough setup currently that doesn't draw too much power and a fan pushing less air is perfectly OK. If you're planning for a bigger upgrade in the near future and you swapped the original fan for a fan that pushes >50% less air, then most likely the maximum airflow available is too little in the future.

If this is your first experiment and you’re a bit unsure, don't go for a big drop in the fan airflow. Go for <20% airflow drop or if you think you know what will be OK, even 30-40% maybe then.

Is the fan ramping up quickly and staying there even when idling?

Something is not right then. What kind of a PSU do you have? Some old pinp-pong brand rated ~235W and you're running your brand new top of the line setup with it? If so, read the recommendations from the articles section and run to the closest computer store :)

Or are you running a light or medium setup with a decent, maybe even SPCR recommended 300-350W PSU? This could well be a matter of airflow. Is your CPU exhaust sucked in straight inside the PSU? Consider ducting the CPU exhaust air to a case exhaust fan. Check your case's general airflow. Do you have decent air intake? [url= ... h+air+duct]If you have a single 80mm fan PSU, try building the 5.25â€
Last edited by Aleksi on Sun Nov 12, 2006 12:48 am, edited 5 times in total.

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Post by Ralf Hutter » Sat Apr 02, 2005 7:22 am

Aleksi - That's a very nice write-up. Good work!

To show my appreciation, I'm going to let you have the use of the SPCR condo in Monte Carlo for the weekend of the GP. ;)

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Post by nici » Sat Apr 02, 2005 9:54 am

Ralf Hutter wrote:Aleksi - That's a very nice write-up. Good work!

To show my appreciation, I'm going to let you have the use of the SPCR condo in Monte Carlo for the weekend of the GP. ;)
*Starts writing a PSU modding article* :lol: No seriously, good work :D

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Post by Aleksi » Sat Apr 02, 2005 9:55 am

Thanks Ralf and Nici for the nice feedback. :D Truly appreciate it!

I'll try to get the same comment from my coming post about modding the Neopower. :wink:

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PSU mod sum up

Post by Thomas » Wed Jun 22, 2005 5:17 am

Aleksi, I find your guide very usefull. It's a nice guidance in locating the source of the PSU noise.

However, I believe one issue is missing, namely decoupling the PSU and/or the PSU-fan from the cabinet.

At this point, it's my biggest noise source and I'm looking for inspiration and ideas to eliminate it. So far, I havent succeded during the search, except I found the method of rubber based fan mount.

I'm not afraid of open up my PSU. However, if possible, I would like to avoid it, due to warranty reasons.

Maybe someone can provide a link, or like to share some ideas?

I must say, I'm quite impressed by this site and the people here. Great source of inspiration. I'm impressed by the approach; Clean design of site and PC housings. And especially, cool smarter, not harder 8)

I only have one sad thing to say about this site: I found the site AFTER I bought my latest PC a month ago :cry:

Hmmm. Seems I'm getting addicted to noise-terminating-stuff, ouch. Gonna be fun :)

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Post by Aleksi » Wed Jun 22, 2005 6:04 am

Hi and thank you Thomas!

PSU fans aren't really any different when compared to normal case fans. If you search the forums, you can find different methods for soft mounting a fan. Some use sorbothane between the case and the fan, some use zipties with foam to secure a fan, rubber fan mounts etc etc etc...

Personally I would use (and have used) the rubber fan mounts. They work well and also they do not rise the fan too much. There's always a risk of lifting the fan by using fan mounts, which may cause the fan blades to touch the heatsink.

And yes, I also found this site few months after I purchased my computer :roll:

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Post by Thomas » Fri Jun 24, 2005 11:51 am

Hi Aleksi, thanks for your reply.

I agree with you, there's several posts regarding decoupling a fan. However, I still think it should be a checkpoint in the PSU guide, to check if the fan makes vibrations, which goes to the cabinet...

There might be users who dont like opening up the PSU, and thus might find it relevant to decouple the PSU.

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Post by Aleksi » Fri Jun 24, 2005 12:13 pm

Hi Thomas,

I have to agree with you, the fan mounting should have its own section. I'll try to get a few examples of it on the checklist! It's good though that they are included in the modding pictorials.

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PSU Mod Failure....

Post by Bluefront » Sun Aug 27, 2006 4:04 am

Well too bad. I had this PSU mod figured into a new case airflow technique. I'll have to rethink this one.

Its a Fortron 300w Matx PSU. I wanted to blow the exhaust upward through an opening in the top of this tower case project. So to do this I simply reversed the 80mm internal PSU fan. The intake is now where the PSU would normally exhaust.

I have used this particular PSU's good. And the MB and HD were removed from a working system.....they're ok. The PSU is over-heating with the airflow like this, even though the output temps are never over 39C. Some particular internal component is not getting enough airflow.

I can fix the overheat problem my hanging another fan outside the PSU blowing in the intake opening. No siolution in sight if I want to use the Fortron fan control. Arrg...I'll have to flip the fan back to stock, and redesign.


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Post by Bluefront » Sun Aug 27, 2006 10:40 am

Well I don't give up easily....I had another of this same PSU. I figured it's tolorance for higher temps might be a little better. So I tried it. Bingo.....Works fine so far. I even put a less powerful slim 80mm fan it it, a Sanyo Ace 80mm. This is one of the quietest 80mm fans at any speed....most expensive also. Anyway I can now get on to the rest of the project. :D

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Post by meansizzler » Tue Oct 30, 2007 2:53 pm

Why solder the fan to the PSU?, you can just hook it up the the Mobo Fan Header?, that's what I did...

As for the 120MM nexus it generates a clicking noise when used horizontally, so no good for PSU, I put a Scythe 1200RPM in an Enermax 500W, works great, no probs at all, a little loud though, but even a 2.5" Laptop drive is loud to me... :D

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Post by funnyceline » Tue May 11, 2010 7:19 am

I am planning to mod my psu cooling unit. I think I need some fans for the exhaust part. To make it cooler inside the psu, I am thinking of putting more exhaust fans in order also to take the warm air out.

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