What is your take on converted desktop power supplys?

Question

Title kinda says it all but let me further elaborate.

What is everyone's opinion on pc PSU's being converted to a bench PSU. I probably have 10's of dozens of PSU's that either been scrapped for their innards or torn from old dumpster PC's with the ones still in tact and working I'm considering making a bench power supply.

I have two questions one is my personal kinda need a little advice question and the other more towards what everyone thinks.

There is the good ol' question "what one should I use" I have supply's ranging from 100w-900w and going from zero energy efficiency to 80+ gold. So I'm wondering is should I compromise power efficiency for a little extra safety and lower wattage so I don't have an over kill bench supply, or should I go for over kill because all of my efficient supply's are 600w + .

The next question is what do y'all think about taking a pc supply and recycling it to a bench supply. is it worth saving the environment by recycling or would people be better off striping them down / sending them to recycling places,and then buy a brand new supply.

Either way I will be making a bench supply from a old PSU due to money constraints, that does not change me wanting to know your opinions, so shoot away!

let the comments begin!

jw0752 · Accepted Answer

Hi Gabe, I converted a computer power supply to use on my bench. Michael is correct that you may have to mess with the mains in order to turn it on and off with a switch. This can be dangerous. When I use my converted supply I always fuse the supply lines as I am not sure how well the supply is designed for over current situations. There are different supplies out there and they do not all modify to bench in the same manner. I will look for a link to some instructions for this conversion that I saw a while ago and I will repost if I can find it. In my case I ended up with + and - 12 volts, +5 volts and +3.3 volts all at reasonable or above need levels for my bench projects.I put banana jacks on the ends of the existing cabling and I left the existing case intact for safety. Here is a picture of my completed unit. John

michaelkellett · Answer

If you need a multi-hundred watt 12V or 3.3V supply with almost no load protection then a PC supply is OK.

Most bench supplies have adjustable output voltage and current limits. If you can live with a 0-10V supply using the PC supply as a 12V source may work fine and save you a little money.

For bench work you need to be able to set the current limit from 10mA to maximum within a few % - so you can protect the thing you are testing. The output voltage needs to be adjustable but if funds are tight you can use a standard DMM to set it up and avoif paying for a built in meter.

I wouldn't advise trying to modify the PC supply itself because all the mains safety stuffs goes out of the window as soon as you open the case.

MK

jw0752 · Answer

Hi Gabe, Here is a link to a u-tube video on making a conversion. http://www.youtube.com/watch?v=z2oSFpKh_Uw John