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External power supply for SFF

Last response: in Components
August 12, 2005 4:13:44 PM

I have an AOpen EZ65 with a 220 W power supply. I bought a BFG 6800 OC AGP card and now my pc won't start unless I remove the card. I also tried removing the DVD writer and floppy drive to give the card more power but the cube won't start unless I remove the card. I'm pretty sure its because of the power supply, which sucks at 220W. Is there any way I can get another external power supply and use that to power the graphics card? I don't care about the cables and the noise, all I want is the 6800 to start working with my current setup:

AOpen XC Cube EZ65
220 W PSU
P4 2.8 Ghz HT
256x2 PCC3200 ram
80 GB Maxtor HDD

Has anyone tried running two power supplies? One for the graphics card and the other for the PC ? I checked Aopen's website and there's no upgrade for my current PSU :( 

August 13, 2005 12:18:20 AM

Thanks for the link. I'm not sure if that power supply will fit in my Cube. AOpen has its custom made crappy PSUs. They don't believe in making upgraded PSUs for the systems they sell. Add to it horrible customer service. NEVER buy AOpen.

Sorry for being a jerk, but what's the paper clip trick ? Will it let me run 2 PSUs at the same time?

I wish Tom's hardware did this "experiment" (running 2 PSUs, one for graphics and other for the rest of the comp.)and help guys like me stuck with a weak system.

Thanks for your reply.
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August 13, 2005 12:48:25 AM

First, will anyone else chime in on this one?

Second, your not a jerk for asking a question. This is a community that voluntarily helps others. The paper clip trick can viewed here. Read the instructions carefully.

The only other thing I can recommend is purchasing a new, non-SFF, case, perhaps a slimline (HTPC). If you really like SFF's, I think a few employ microATX PSU's but I could be wrong. Or, if your handy, mod the aopen case to extend the psu cradle, so you can use a bigger psu. If you decide the last route, research if it's feasible. If the Aopen mobo is proprietary, there's a chance only Aopen approved psu's work, a la Dell.
August 13, 2005 5:48:45 AM

Thanks for the links. Does this mean I'll be able to run two PSUs at the same time?

I had another idea.. I'd like your opnion on it. If I just replaced the power supply with a new one, what should I consider to make sure it doesn't fry the motherboard?

One more question. Whenever I plug the card into the AGP slot, a red led next to the AGP slot lights up. Its the first time I've seen it, cos it never showed up when I plugged in my friend's 6600 or my "old" Ati 9800 pro (both need a 300 W power supply but they worked fine on my comp.). Anyone know what that could mean? Aopen, doesn't answer my questions.
August 13, 2005 6:58:46 PM

Technically, yes. Here's the problem: The paper clip method creates a short and the psu will eventually blow if there's no load. It's very useful for testing purposes, though. As a permenant solution, I'm hesitant in recommending it, for one must set certain parameters to minimize hazardous conditions that may occur. Imagine if your video card just died for some immediately unexplainable reason. Because the card was connected to the external PSU with the paper clip, the PSU is at great risk for spectacular failure. Therefore, the more components connected to the PSU, the better. Furthermore, instead of a paper clip, solder a wire to the leads. Now this solution is more appealing, but I still don't recommend it. Pursuing it, no doubt, requires more research (and another opinion).

Well, honestly neosapien, the mobo situation bewilders me. My gut instinct, and because Aopen designed most of the components - including the mobo - says only Aopen approved PSUs are eligible.

The red light means the video card and mobo/PSU don't agree. It's very possible because your psu is puny and cannot support the video card's power requirements. Since it's a proprietary mobo, there's also a chance there's some conflict with directly between the mobo and the card, even if you have an ample PSU. I'd inspect the PSU and the mobo, in that order.

I found a link I thought you might like. It talks about adding a second (ATX) power supply. As I said, you have to watch the load. I would wire at least one additional load, besides the video card, such as a fan, LED, anything reasonable and sensible.

What's the pin count on your mobo or psu, btw?<P ID="edit"><FONT SIZE=-1><EM>Edited by poly4life on 08/14/05 03:31 AM.</EM></FONT></P>
August 17, 2005 6:40:54 AM

My mobo's got 20 pins just like the pic on the link you posted. Its a standard ATX connection. I'd love to plug in another power supply, but will it blow up my mobo ? I found out that the 6800 had a broken resistor (it seem like a big one) , so I returned it to the store. They're outta stock, but will give me one as soon as they get it. Could this have been the reason for the red led lighting up ?

Is it worth running a second power supply or should I take the risk and replace my current one with a better one? Will a bigger power supply blow up my mobo ?

Here's the manual for my comp.

The power supply looks normal, but I'm not sure if AOpen went thru the trouble to make a special one.<P ID="edit"><FONT SIZE=-1><EM>Edited by neosapien on 08/17/05 02:47 AM.</EM></FONT></P>
August 17, 2005 7:45:34 AM

If you have the budget, and can still refund for the Aopen rig, I'd recommend purchasing the Coolermaster ATC-620C-BX1 Aluminum Mini Tower Case ( If your committed to Aopen...well, that's your decision.

A burnt or broken resistor probably impeded the card from running, combined with the fact that your PSU is completely insufficient for your situation.

It's difficult to say if it's proprietary or not. In my opinion, more in-depth examination is neccessary to arrive at an answer. Or, assuming Aopen technical support is adequate, they should know. Their answer will determine if the mobo can handle a bigger PSU. And, no, a bigger PSU won't damage your mobo (presuming Aopen bestowes you the "OK").

I would avoid employing a secondary PSU; instead, I'd purchase a case which can house standardized components, like an ATX PSU and microATX mobo. If you wish to pursue the aforementioned, somewhat, lofty project, you must understand two PSUs powered simultaneously necessitates additional care and monitoring of the rig.

Good Luck.
August 18, 2005 12:02:56 AM

Wire the green wires from both supplies together (leaving one in a 20-pin plug of course), and the black one next to them too.

That should make the two supplies turn on together.

Share out the molex plugs between stuff. You may as well spread the load out. :smile:

<font color=red>"Life is <i>not</i> like a box of chocolates. It's more like a jar of jalapeńos - what you do today might burn your a<b></b>ss tommorrow."
August 19, 2005 12:03:15 PM

Actually, if the second PSU is sharing a ground with the other one (i.e. is bolted securely to the case somehow) then you won't need to do anything with the black wires. In fact you could dismantle the supply, and remove all the leads going to the 20-pin plug except the green one. Obviously be very careful that you don't cause a short anywhere, or you could blow stuff up.

An ATX PSU uses the green wire as the on switch - connect it to ground and the PSU will turn on you see. (that's all you do with the paperclip trick, connect the green wire to the black(ground) one next to it).

<font color=red>"Life is <i>not</i> like a box of chocolates. It's more like a jar of jalapeńos - what you do today might burn your a<b></b>ss tommorrow."
August 19, 2005 12:07:13 PM

And to answer your questions, a bigger supply (wattage-wise) will NOT damage your motherboard (assuming it's working properly) You could shove an 800W supply in there, it just wouldn't be operating at anywhere near peak load.

<font color=red>"Life is <i>not</i> like a box of chocolates. It's more like a jar of jalapeńos - what you do today might burn your a<b></b>ss tommorrow."