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Using 2 power supplies

By hipal ·
Is it possible to use 2 PSU to control components within the same computer? I am suffering from lack of power to run my DVD burner and HD at the same time. when booth are running power shuts off. I have an old power supply but the power on/off is controlled by a switch through the motherboard. I can't find a good wiring diagram for the wiring of the PSU so that I can bypass this switch. If I wire one PSU to the DVD drive and leave the current one on the existing PSU will it still work properly? or I also wondered if you could simply spice the two components together? Running both off of the same switch. Any Ideas would be helpfull. Thanks

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by dmiles In reply to Using 2 power supplies

No I donot think so,just buy a larger ps,you should be able to get a 400W or 450 at a reasonable price.

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by TheChas In reply to Using 2 power supplies

There are server and rack-mount PC chassis that do allow the use of multiple power supplies at the same time.

However, in your situation, dmiles is correct. Your BEST option is to just install a larger power supply.

Assuming yours is an ATX style system that uses a standard size ATX power supply, you should be able to find a 400 to 500 watt power supply for under $20 (US).

Some OEM PCs use micro-power supplies. If yours is one of these, your options are more limited.
"IF" your motherboard is a standard micro-ATX style motherboard, I recommend just getting a new case with a larger power supply.

If your motherboard and / or system components will not fix in a standard case, I recommend a new PC.
Either build one yourself, or buy one with the power you need.

Alternately, if you have USB ports, you can install your DVD drive in an external drive case and power the drive from an external power supply.

On an ATX system, the front panel power switch just signals the power supply to turn on at full power.
A "power good" signal from the motherboard tells the power supply to continue, or shut down.

Your problem may not be an undersized power supply, but may be heat or some other problem.

Make sure that ALL cooling fans are spinning properly, and that your vents are clean and free of dust.


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by HAL 9000 Moderator In reply to Using 2 power supplies

Well as both the previous respondents have said it would be better to just go with a bigger power supply. If you can fit a second PS into the case you should be able to use a standard Antec, Evermax or the like PS. Just a note of warning though with the top of the range Antec's they have a 24 pin ATX plug and not the 20 pin ATX plug which is the norm.

As for splicing the 2 together in theory it is possible but it would at the very least be messy and you would have to do it absolutely correctly or you could destroy the M'Board CPU & Ram as well as any plug in cards and most likely the interface on every drive as well. Before you even begin you would have to remove everything except the existing PS from the case and cave a hole in it to mount the second PS then refit everything. You could conceivably use an ATX PS Tester to keep the second one running but I do not know how long this would last or you could splice the wires to the ATX connector together onto one ATX plug that will mean all 20 wires being spliced to the same pin on the different plug. I also do not know if this will work as I've never actually tried it because it would be a massive waste of time and potentially dangerous to the computer itself. The way that ATX PS work is that you switch on the active which starts the M'Board running momentarily and then the M'Board sends a signal to the power supply telling it to keep running now with 2 PS connected I do not know if that signal would be strong enough to actually get the required response and keep the PS's running.

On a normal Rack mount Redundant PS one plugs into the first PS and then they keep running off the signal from the M'Board which triggers the first PS and they subsequently through its own circuitry triggers the second PS to work.

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by HAL 9000 Moderator In reply to

But even the most basic off the shelf box should have a big enough PS to power a Burner, HDD and M'Board/CPU/RAM combination. Your problem sounds far more like a bad power supply that is in the process of dieing rather than not enough available power.

I would do as Chas suggested change the PS to something much bigger and a well known Brand Name as well because they just work better. If you can not fit a standard ATX PS into the case then most likely you'll be unable to fit that M'Board into a standard case owing to the way it has been made for a OEM manufacturer. But something rated to 300 W should work that configuration with ease although for the sake of a few $ I personally would go for something bigger so you have a lot in reserve and the likelihood of the PS burning out by being overloaded is reduced to almost nothing.

Have you also tried using just the HDD alone by disconnecting the burner? Then if that works which I believe it would you can create a CD Boot disk or use a Live Linux CD and disconnect the HDD and try booting from the burner to see if that works as there could be something electrically wrong with the burner. While you are at it also check for any trapped wires from the PS as they could be caught and earthing out on the chassis and be causing your problem.


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by osumiller In reply to Using 2 power supplies

These are all good comments. One other item that could cause this scenario is either a really strange driver, or trying to overclock the CPU. Is this a newer computer? What video card is in the system? I have seen video cards which could cause such a disturbance, but it has been a long time since those cards were produced. All in all, the most probable issue is either a bad power supply, or heat within the case. Bad ram could cause this as well.

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by wlbowers In reply to Using 2 power supplies


You can get a 500watt supply for less than $30 shipped.

What you plan on doing is not prudent on a system not designed for it.

Smoke! Smoke! Coming out of my case.


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