So I’ve been working on building my own resistance soldering unit for a while now, and the original attempt using a automobile charger didn’t work as the unit didn’t have high enough amps at lower volts. So today, I stumbled upon a $4 computer power supply unit at Goodwill, I bought it thinking I could make it work.

Here’s the specs;

DC output +3.3V @ 28.0 A, +5V @ 34.0 A, + 12V @ 21A, -5V @.5A, -12V @.8A, +5Vab (what’s the ab stand for?) @ 2.0A

After looking at all the specs online it seems that the 12V @ 21Amps should work just fine for resistance soldering. But here’s my question, because the unit has a bunch of outputs should I design something to work with each of the ranges, or just concentrate on the 12V?

Thoughts?

Craig - I used a similar power supply for a resistance soldering unit that I built some years ago and it worked well - depending on the vintage of the supply you may need to jumper two wires to power it on - there are lots of posts on the web that explain the procedure - such as:

http://makezine.com/projects/computer-power-supply-to-bench-power-supply-adapter/

dave

David,

Thanks for the link. I messed around with it a little yesterday and couldn’t get a reading with my multi-meter, but it sounds like from your post and the link that it needs a load to power it on. Thanks!

Stick a 12 volt taillight blub from a car on the 12 volt line to give it something to do… that may bring it to life.

dave

I pulled it apart and checked various parts with the Ohm meter, and it looks like the fuse is burnt out, so I’ll either have to replace it or bypass it. But I think it should work still.

Do you have pictures of your unit that you built?

Craig Townsend said:

I pulled it apart and checked various parts with the Ohm meter, and it looks like the fuse is burnt out, so I’ll either have to replace it or bypass it. But I think it should work still.

Do you have pictures of your unit that you built?

No photos, Craig - I put it together 8 or 10 years ago, used it for one project and retired it! The power supply fed two thin carbon rod terminals and was activated by a foot switch - it worked rather well.

dave

If you get no output with the fuse repaired a load on the 12V line post a picture of the multi-pin motherboard connector. I can probably tell you which wire you will need to hook up to get it to run. Most newer supplies have an ISGOOD line. Not sure which off the top of my head, but it needs to be held either high or low within a few hundred milliseconds of the supply being turned on in order for it to continue to supply power. On newer supplies there is also a START line which tells the supply sitting in stand-by to power up.

Thanks Jon I’ll keep that in mind. I won’t likely get a chance to pull it apart and really work on it for a couple of weeks as we are in the middle of a move. The deal was too good to pass up…

Any other suggestions I should be on the lookout for?