New PSU's keep failing when peripherals connected

ptaylor999

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Aug 23, 2011
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Hi all,

As the subject line (plea for help!) says, my brand new Corsair RM550x power supply will not boot when there are any peripherals connected to it. Not even just one! When it is connected only to the ATX and CPU on the motherboard, I get a blue power light and the fans all start spinning.

This is for an HTPC, so I can't imagine 550W is not enough for three hard drives, a blu-ray player, and a sata controller.

I am wondering, could this be a motherboard issue? Would the computer power up at all if the motherboard were damaged? The reason I ask is because I am replacing a PSU that died a few days ago. I heard a loud POP, and the whole unit shut down. I did the paper clip test on the PSU and yep, it was dead, I then tried a EVGA SuperNOVA 750 B1 80+ BRONZE PSU, but it died as soon as I powered it up (all peripherals connected), with a wisp of smoke drifting out of the PSU itself. Thining and hoping I just got a faulty PSU, I purchased the Corsair. So, this is my third PSU. It has not blown up, but it will only power up when there are no peripherals connected.

I have looked at both sides of the motherboard and it looks fine. No black marks or melted solder anywhere that could be causing a short, as far as I can tell anyway.

I'm at my wit's end and could sure use some expert advice.

Thank you!
 
Solution
Pull all of the hardware connected to the motherboard out of it.

Leave just the Cpu, and a stick of memory in the first memory slot of the motherboard

I will take it you are using a motherboard with it`s own on board video solution on it.

If so connect your video cable to the outputs on the motherboard.

Then power the system up.
Read Motherboard Short circuit if it happens when the system was first built and powered on first time.
If it powers up fine. Read on.

Now depending on how many memory sticks you have, try each one at a time in the first single memory slot of the motherboard testing to see if the system powers up right.

If you place a memory stick in a memory slot and the system does not power up, then it can mean that...

ptaylor999

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Aug 23, 2011
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18,510


Thanks for the response. I've already tried that. With even one peripheral connected, no matter which one, it won't boot. I'm stumped! Is it possible that 550w is not enough?

 


No. I would say an RMA for the motherboard is in order. What PSU did you originally start with?
 
Pull all of the hardware connected to the motherboard out of it.

Leave just the Cpu, and a stick of memory in the first memory slot of the motherboard

I will take it you are using a motherboard with it`s own on board video solution on it.

If so connect your video cable to the outputs on the motherboard.

Then power the system up.
Read Motherboard Short circuit if it happens when the system was first built and powered on first time.
If it powers up fine. Read on.

Now depending on how many memory sticks you have, try each one at a time in the first single memory slot of the motherboard testing to see if the system powers up right.

If you place a memory stick in a memory slot and the system does not power up, then it can mean that memory stick is not working or has been damaged when the power supply unit blew.
It will prevent the system from powering up as it is classed as a short circuit.

If the board refuses to power up with the basics of just the cpu fitted, and a memory stick it`s a good indication also that when the last power supply blew it damaged the motherboard.

The only way to confirm this would be to test the memory in another system, and or a Pci-e based graphics card if you were using one in the HTPC other than a on board graphics solution of the motherboard.


Motherboard Short Circuit.

If you just built the system, and the RM550x was brand new, and it was the first time you powered the system on ptaylor999.

And it blew up straight away.

It means that when you fitted the motherboard to the motherboard mounting plate of the case.
That you have left a board standoff that keeps the motherboard from touching the metal back plate in a place where there is no pass though screw hole lined up with the motherboard it`s self.

This will cause a short circuit on the back of the motherboard, and you will have to remove the board to check.
The other case is not fitting any motherboard standoffs at all, meaning the whole board is touching the back plate of the motherboard mounting plate. That is a complete no no.

A short circuit will prevent any power supply full powering up the system.
And it can can happen when a system part is broken or damaged, it will treat it the same as a short circuit of the system preventing the power supply from fully powering up the system, as a fire precaution.

Once the circuit protection of a power supply is triggered.
It is retained, and must be reset to clear the tripped circuit.

Or the power supply will never fully power the system up.

To reset the circuit.
Flip the rocker switch on the power supply over to its other position.
Remove the plug from the wall from the power cord connecting to the PSU.

Leave it for ten seconds.
Plug it back in, then return the rocker switch on the PSU back to its other power state.

 
Solution

ptaylor999

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Aug 23, 2011
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Wow. Thank you very much for the detailed advice and instructions!

The computer was originally built in 2011, so it's a good 5 years old, but has been working without incident until the other day.

I have not hooked up a monitor to the computer yet, since installing the new PSU's. Do you think this is necessary given that the board seems to power up fine when only the ATX and CPU power connector are installed into the PSU and the motherboard? When I say that the board powers up fine, I mean that the case fans and the CPU fan fire up, and the case power light comes on. Excuse my ignorance here, but I haven't built a computer system in 5 years and really just kind of Googled my way through it. Given that info, I'll do your testing procedure if you think it's necessary.

Thank you!