Gee, don't you hate it when you go to turn on the computer, expecting everything to go as normal, and then nothing happens? You push the button again and again, but still, silence? Yeah, I know what you're thinking: either the cord's loose or I'm an idiot and the power's out again. But nope, both are normal, so the only thing left is something wrong with the computer. Well, more often than not, it's a failed power supply. Most of the time you'll get the dreaded dead response, others you'll get neat sparks and smoke. Either case, it's not good.

Anyway, after that's all said and done, and the power supply's been replaced, what you're left with is a dead PS. My question is, how would one rebuild it so it's functional again? I've had several power supplies die in my times, and I'm sick of basically throwing them out. Are there any diagrams online somewhere that people could point me at telling me how to rebuild them?

ah in short, a good PSU unit is about 50$, i got a Antec TruPower330wt, and its done me very well. just to be safe, i set another old one with a switch to run all the fans when i game, then hit them off, leaving just my Watercooling to go in silent mode while i go to sleep.

The problem usually with a bad PSU is the magic smoke left. Its a fact of life, things get hot, banged, all whatever and hell, but when you see the magic smoke leave (usually bluish or white) they are definitly shot. cause the magic smoke is put into the circuts and makes them go.

now, all joking aside, the problem usually is bad capacitors. so my idea, would be to run a current through it, something small. if you had the diagram, you could check at certian points, slowly narrowing down the search. in the end, youd probably isolate a capacitor or 2, which are shot. so youll need to find the exact specs on them (wts, resistance,. charge held, capatiance rate. dunno, read the book on electronics, promtly forgot it 10 seconds later like any sane person should), go to radioshack, find the exact one, break the old one off, solder the new one in.

me, personally id pay the 50$.

How about this? When you get a physical frying of the power supply - with actual smoke - it can be pretty easy to fix. You can crack open the PS and find the toasted part, often a capacitor, unsolder it, read the numbers on it and buy a replacement at your local electronics store. Simple enough, right?

If you don't get an actual burn-out, it can be hard to spot the problem without testing equipment. Look closely at the tops of the capacitors (the ones with a silvery looking top) to see if they have bubbled up to look rounded on top instead of flat. That's usually a sign that the cap has blown.

Usually it comes down to one part frying, so a full rebuild isn't necessarily what is needed. If multiple parts are fried, that is the result of something really nasty like a near-direct lightening strike or a fan dying which stops the PS from cooling and can melt several parts rather quickly. Sure, shelling out $50 for a new PS is great if you can do that, but it isn't always possible for some and others just like the challenge of a repair.

Oh, and sometimes it will be something as stupid as the power switch breaking on the inside. Happened to me once and thought it was the power supply.

I have been learning much about power supplies lately. You can read about one of my fun adventures here: http://www.astahost.com/index.php?showtopi...97&st=0&p=19220

pretty often in PowerSupplly module burnes out one little fuse, and it looks like a tube of glass 3mm diameter and 1,5 cm long, with a thin wire inside, That is a fuse for power overload protection... Now if that wire inside a fuse is burned out, you will see that it's cracked, and all you need to do is to buy a new one in your electronis store, or if it's kind a emergency you can replace a wire with a homemade one (get it somewhere from old elec. equipment...) but I stronlgy recomend that you buy an original fuse.

Thanks guys. As I have very little experience in circuitry, I just went out and bought a new power supply. Perhaps one day I'll get the gumption to fix my old one, or perhaps I'll just hock it on eBay. Either case, my woes are now over (hopefully), and I can enjoy my old computer once again.

Hi

I have a 19 volt 3.42 amp (model no.SADP-65KB B)laptop power supply. Last night when I switch it on its not working...I open the casing n find that a SMD transistor and to resistance is burned.I cant see the transistor name n no. coz it burned the part name on PCB is Q2 for transistor n R20 n R23 for resistances. Can anyone know about this schematics n help me about finding these parts. I can replace the components if I find the part name. Thnx



-sachin arora