I seem to be making a habit of this but...

[Wolfe Tone]

I'm having yet more problems with my PC. I got my new graphics card this morning, a Saphire Radeon 9700 pro all in wonder. I go to install it, connecting everything correctly including the extra power cable. However when I go to turn it on the fans and my neon light come on for about 2 seconds then everything turns off. I've reinstalled my old graphics card so I could post this. I'm going to assume that it is a power problem and I don't have the extra juice needed. I have an enermax 350W PSU (I think) and I'm running my motherboard, cdrw, dvd and a 2 hardrives of it, as well as a few case fans. I have also tried connecting the power cables in a few different coniguration yet it was still no go. I think I may have a solution, but I'm not to sure how safe it would be (which is why I'm posting here.) I have an old PSU from my old machine (which I don't need, It has been totally stripped down, all it is is a mother board, case and PSU.) I figure I could connect it to my new graphics card to supply the extra power needed. The thing is there isn't enough room in the case so it would have to be kept out side. Does anyone think there would be a problem with that or should I go ahead and try?

 

[Wolfe Tone]

I went ahead and tried wiring the smaller PSU up to the graphics card and it didn't work. The PSU didn't even kick in. Could someone tell me how to make a second PSU work.

 

[Centrifuge]

First off, Let me suggest that you simply buy a more powerful PSU. This sounds dangerous...

To answer your question: the new PSU needs to be connected to the MOBO in order to work, otherise the PSU fan and voltages can't be monitored.

 

[CrackedCrystal]

You do have a weak PSU. But I do not think you should be messing around with dual PSUs if you don't know what you are doing. Like Centrifuge said, it could be dangeous.

But you actaully do not need it connected to the motherboard. You could rewire the pins to make a common ground, then place a switch on the turn-on circuit. That is why the second didn't turn on, I can't remember the pin numbers off hand though. However, if you do this wrong, It will completly ruin your computer, and possibly electrocute you.

Also, you do not want a different power supply powering your video card than that powers the MOBO. The AGP port supplies power as well and may cause damage is the voltages aren't correct because two different units power things.

Be safe, if you think its a PSU problem, just buy a bigger unit (maybe 450W). Its not worth saving the $40 and risking your entire computer, not to mention your safety.

 

[Wolfe Tone]

It doesn't seem to be a lack of power problem. I tried it in my friends machine who has the same motherboard (Abit NF7-S) and he has a smaller power supply (300W I believe.) Does anyone have any other suggestions, as I could lose quite a bit of money.

 

[Lucky]

350W should be plenty for your system. But there are many power supplies that have much less than the watts written. Tom´s Hardware made a nice test with 400W PSUs shutting down at 320W or so and some even burning out.
So don´t try to save costs on this end. Check some reviews on your PSU type, maybe you´ll find some.
But even 300W should be plenty as you don´t have a ton of different drives.

Originally posted by Wolfe Tone
I went ahead and tried wiring the smaller PSU up to the graphics card and it didn't work. The PSU didn't even kick in. Could someone tell me how to make a second PSU work.

As Crystal said, it is possible. But you have to rewire the 3? wires that go to the power switch. Some older PSUs have a direct connection from the power supply to the switch, but most go over the motherboard connector. So unless you have a description which pins of the MB connector are for the power on switch, don´t mess with it. If you have no electical engineering knowledge, i.e. if you don´t know how to skin and solder wires to a new switch, or the one already in use, DON´T mess with it.

Using 2 PC power supplys for one comp is only for those that know how to handle it!!!

But once again, 350W should be plenty.

Try disconnection all but your main harddrive and also all the fans you don´t need (only case fans!!). And then try it again. If it still fails, there might be something wrong with the connector or the card itself. If not, attach the disconnected drives and fans one by another. If the comp switches off again, your PSU is indeed not supplying the 350W, you need a new, better and more reliable one.


P.S.: Enermax PSUs are usually rather good, so I´d be surprised if it´s too weak.