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!
Hereâ€™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 â€“ 25CFM
Panaflo (MMM) 80-M1A â€“ 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 youâ€™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=http://forums.silentpcreview.com/viewtopic.php?t=18551&start=0&postdays=0&postorder=asc&highlight=psu+fresh+air+duct]If you have a single 80mm fan PSU, try building the 5.25â€