replacing internal PSU fan

[xmountainxlionx]

i want to replace the internal fan in the PSU. is this safe to do, and worth the effort(new fan has leds), if so how would i go about doing it.

the old fan is connected with a weird 2 pin connection and uses just a red and a black wire. so i thought my best bet would be to cut the wires on the old fan and take the wires still connected to the psu and put them to the cut wires of the new fan, and the heat shrink them together.

any thoughts?
cause im going to bed <<<<yawn

 

[Frick]

It's doable, just be careful. A three pin connector will work fine on those two, just force it down so the black/red wires are connected. It'll run on max speed though, if it's a thermal controlled fan.

Remember: BE CAREFUL! Before you start, unplugg the powerchord and leave the computer as it is for some time. Then you can take the PSU out and start working.

Also, BE CAREFUL.

 

[Zedicus]

unplug the power cord from the computer while the psu is still in. then press the pwer button on the computer, a lot of times the fans will spin for a split second, this will help drain the psu and all thouse meety caps. still it would b wise to not go poking anything other then the fan header.

its actually possible to change resistance on the pots and adjust output voltages on the rails, this is nice if yur MB doesnt support changing voltages, or if u run out of settings in the bios. usually its more trouble then what its worth though.

my psu i stuck a led fan in and sleeved the entire thing and upped the 3.3 rail voltage a smidge. a few years later it died do to an unrelated problem, i didnt figure pc power and cooling would want to mess with it but i sent it in anyways, i got an email from one of the techs saying he really liked my work and that my repaired psu would b sent out in about a week.

so props to pc power and cooling, who is now owned by OCZ, thouse r 2 of my favorite companys based on product quality and customer service.

 

[Fuse-Wire]

Remember: BE CAREFUL! Before you start, unplugg the powerchord and leave the computer as it is for some time. Then you can take the PSU out and start working.

Also, BE CAREFUL.

1 more thing (uncle from jackie chan??) always ground yourself on a bare bit of your tower to get rid of any excess static, prevent any damage to your system doing that

 

[keakar]

i want to replace the internal fan in the PSU. is this safe to do, and worth the effort(new fan has leds), if so how would i go about doing it.

the old fan is connected with a weird 2 pin connection and uses just a red and a black wire. so i thought my best bet would be to cut the wires on the old fan and take the wires still connected to the psu and put them to the cut wires of the new fan, and the heat shrink them together.

any thoughts?
cause im going to bed <<<<yawn

you cant do it that way, but you can do it.

psu fans are made differently so they can start and run at lower voltages which is why the psu starts the fans out at just 5 volts at start up and slowly increases volts according to the temps so it speeds up as it gets warmer by giving it more volts. if you wire a case fan to the internal wires for the fan, it will try to start but not have enough power so the psu will run for a short time without any fan (very bad thing) till it gets hot then the fan will be getting high enough volts to start and run.

just install your case fan as you intended on doing but run the wires along with the wiring harness and then plug it into the molex connection for your dvd drive (it should be long enough to reach).

if you want a clean look and would rather not do this then solder the wires directly to the board inside the psu but not to the old fan connection. the black grounds are all together so thats easy, the red goes to the yellow wires so find the rail you want to put it on and solder it to that terminal.

 

[Zedicus]

thats not always tru, a lot of psu's just run the fan wide open all the time with no temp monitoring. ive ran across one psu that ran the fan at 5 volts all the time. and even on the ones that do temp sensor the fan. most 80mm case fans will start up and spin off of 5 volts so they will work fine and auto adjust speed just like the other fan. its only when u start getting up into the higher cfm 80mm fans that they wont run on 5volt. any of thouse cheep led fans will, or all the ones ive tried will atleast.

also some psu's dont slowly increase voltage, they start out at 5volt and once a certain temp is reached they go to 12 volt.

 

[keakar]

thats not always tru, a lot of psu's just run the fan wide open all the time with no temp monitoring. ive ran across one psu that ran the fan at 5 volts all the time. and even on the ones that do temp sensor the fan. most 80mm case fans will start up and spin off of 5 volts so they will work fine and auto adjust speed just like the other fan. its only when u start getting up into the higher cfm 80mm fans that they wont run on 5volt. any of thouse cheep led fans will, or all the ones ive tried will at least.

also some psu's dont slowly increase voltage, they start out at 5volt and once a certain temp is reached they go to 12 volt.

case fans show minimum starting volts as 6v because this is the least volts it will start at reliably.

these are typical case fan specs:

APEVIA CASE FAN SPECIFICATIONS:
Model No. CF4S
Material Transparent PU plastic
Color Clear
LED N/A
Dimension 80 x 80 x 25 mm
Fan Speed 2000 ± 10% RPM
Air Power 12 VDC
Noise Level 22.05 dBA

Operation Voltage Range 10.8 VDC ~ 13.2 VDC
Start-up Voltage 6 VDC <<<<<<<< notice the number is 6v not 5v
Rated Voltage 12 VDC
Rated Current 0.25 A
Lock Rotor Current 0.25 A
Air Flow 25.64 CFM

on very very rare occassions some case fans will occassionally start with only 5v but dont start on 5v every time, if it starts 9 out of 10 times you still overheated a psu so is it really worth it to live outside the listed minimum volts the fan manufacturers say you need?

in the case of any fan running on 5v all the time, these are specially made variable speed fans and not just case fans they pop into a psu. if a case fan were put into such a psu if you were lucky enough for it to even start it would only be running half speed and it would not cool the psu and you would fry it, this is why you need to hook it up to the 12v supply. its all about being safe and not damaging stuff.

 

[keakar]

i want to replace the internal fan in the PSU. is this safe to do, and worth the effort(new fan has leds), if so how would i go about doing it.

the old fan is connected with a weird 2 pin connection and uses just a red and a black wire. so i thought my best bet would be to cut the wires on the old fan and take the wires still connected to the psu and put them to the cut wires of the new fan, and the heat shrink them together.

any thoughts?
cause im going to bed <<<<yawn

just unplug your old fan and save it in case you want to switch it back one day.

plug the new fan in by using the 12v 4 pin molex connections.

if you wire it directly you MUST hook it to 12v (yellow wire is +pos 12v and black wire is the -neg 12v).
the red wire from the fan goes to yellow on psu circuit board and black wire from the fan goes to black terminal on psu circuit board, the sensor wire just gets taped off and is not connected.

do NOT try and use the plug for the old fan or you will risk burning up your fan and your psu.

i cant say it any clearer than that.

 

[Zedicus]

man i know what that stuff says, what im telling u is out of all the case fans ive used the all, included the ones i just double checked, will start at 5 volts, heck these will start and run at 4.5 volts. and they r reliable.

before u go an an solder something to the board try it on the fan header in there.

also as for a 5 volt fan. its going to spin slower then a 12 volt one, u seriously think psu manufactures go to the trouble of having special fans made? im sitting here looking at a couple of PSU fans ive taken out of dead power suplys and they all show 12 volt ratings and the exact same specs as cheep case fans.

NOTE: i dunno how many times uve actually asembled this stuff, and pulled a fan header out of a psu or tested the voltage on a fan header, but im not just talking from data sheets, this is actuall personal experience. digital thermal probe and multimeter at the ready.

 

[keakar]

ok then, we both had our say about this and only he can decide what to do now.

you are giving advice that if you are wrong could cost him money and damage if not ruin his computer.

your "man i know what that stuff says" comment says a lot about your facts.

after all what do you have to lose if this poor guy ruins his computer?

 

[Frick]

I'd say just push the 3-pin connector to the 2-pin connector. If it doesn't work, just turn around the 3-pin.

Is that a bad idea, and if it is, why?

 

[Zedicus]

im running standard cheep case fans in several psus, they r all connected to the internal fan header of the psu. i guess the peeple trying to swap fans for the first time can decide which route they want to go.

i recently warantied a pc power and cooling psu that had a led case fan in it and they didnt complain at all or say that it wasn to spec or anything. the tech that worked on the psu sent me an email saying he liked all the stuff i did to it.

i will say it again, im not talking out of spec sheetas and pieces of paper, im talking from personal experience.

modding in any form is taking a risk to begin with.

theres always a risk of damaging yur pc.