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!

  • whats your CPU? As for your mobo, yes, motherboards often die slowly and exhibit completely random errors, especially if some of the capacitors are going. Also, confirm that you are getting clean power and your power cable is in good shape. avoid extension cords or cheap power strips. Many UPSs can tell you about the state of your power, and it sounds like one may be a good investment. – Frank Thomas Aug 11 '16 at 2:37
  • What was the wattage of the 2 old PSU's that died? – Frostalf Aug 11 '16 at 2:40

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