Converting PSU from PC to bench power supply?

[Leezygeezer]

Hi, I have rifled an old psu from my old desktop computer and am wanting to convert it into a bench power supply. I have seen some good tutorials on youtube on converting these over but I was wondering. The unit I have is a modular power supply and I was wondering how this would alter my design? I have tried to attach a photo so hopefully it will be easier to see. Unfortunately I cannot find the data sheet for the psu itself but I have posted a link to try and provide more info.

https://www.ebuyer.com/product/98564

Thanks in advance

 

[Reloadron]

The fact that it is a modular design PSU really doesn't matter. I think I have an old Corsair modular supply around here that died. Do you have the cables? That could be important depending on how you choose to go about this. You can use the cables if you have them or hack the PSU to get to the connections. Just a matter of how you choose to set things up. The electronics remain the same. Pretty much like the dozens of tutorials out there. If you have specific questions just ask.

Ron

 

[carbonzit]

I converted mine (old ATX cube) to a bench supply. It was easy, and certainly doesn't require any tutorial.

I suspect that most supplies one finds nowadays (excluding 20-year-old ones from someone's basement) will be the same general design as mine. What this means is that you don't have to mess around with dummy loads to fool the PSU into thinking that something's connected. (Older PC power supplies wouldn't work unless there was a sufficient load connected to the +5 volt supply.) All you need to do is find the "power on" line and tie it to ground, and the thing will come to life.

Sorting out the wires in the motherboard connector can be a challenge. Some of the "instructable"-type pages on the web aren't totally accurate in this department. I found a good online resource with pin identifications, which I'll post later when I can retrieve it.

And as Ron said, if you have any specific problems or questions, folks here can answer them.

 

[carbonzit]

Sorting out the wires in the motherboard connector can be a challenge. Some of the "instructable"-type pages on the web aren't totally accurate in this department. I found a good online resource with pin identifications, which I'll post later when I can retrieve it.

Here's a useful page giving the ATX identifiers.

 

[timthumb]

i could be wrong but i thought the cheaper ATX power supplies need to be under a certain load to regulate the voltage, just something to perhaps check for with a voltmeter before hooking to circuits.

 

[carbonzit]

i could be wrong but i thought the cheaper ATX power supplies need to be under a certain load to regulate the voltage, just something to perhaps check for with a voltmeter before hooking to circuits.

No; some of the older PC power supplies (pre-ATX) require a minimum load (I think on the +5V line) to work at all. (In other words, no load = no voltage.) Not true with ATX, so far as I know.

 

[ghostman11]

i have done this a fair bit with old pc PSU's, i have 2 ATX that did require a load in the end but most have not, i got round the load issue not by the normal resistor way, but instead because mine were enclosed in box'a i had made i added a fan to the box and used that as the 'load' interestingly one PSU needed it on the 5v and one on the 12v! so i guess its just a question of haveing a play with one

 

[Sceadwian]

I've tested three, all worked fine without a load, though you may get better regulation for pulsed loads if you pre-load the supply a bit, check it on a meter/scope while you're playing with it and watch for regulator swings.