Mobo turns on and off after replacing the PSU


Jan 23, 2010
Hi guys,

Okay I read many posts but still no luck figuring this one out. I have P7P55D-E Deluxe running a i7-860, late last week I started to smell my OCZ 700w power supply burning. I turned off the computer and checked inside, i cleaned all the dust, and tried again, same smell. I assumed my power supply burned out. So I went to the store bought a CoolMax CU 700B modular power supply connected everything up. But still got no power to the motherboard. Thinking I got a bad power supply I went back and got another one of the same kind. Now my motherboard reboots constantly. As soon as I hit the power button the mobo lights up the fan starts spinning then it just turns off, then all by itself it starts up again and repeats until i turn off the PSU. So here is what I have tried.

1. Put only the cpu, heat sink, cpu fan, graphics card, and 2gb memory on to the mother board, still had the same issue.
2. Pulled my motherboard out of the case and put it on a rubber mat and plugged in graphics card, and 2gb memory still same issue.
3. I found out if I unplug the 8 pin connector that goes to the CPU the mobo boots up (but this doesn't help)

Any ideas on what could be the issue, I was thinking the power supply but the manual says it supports i7. I did notice that the amps where a little low compared to the OCZ 700W.



How much is the amount of amps you notice.
Try it with cpu, ram and hard disk only do not use graphics card
If the 12v rail reading is at least 11.7, then you're ok; most are within +/-.5%. The power supply may have damaged your board. But if you can get ahold of another ps for testing, that's what I would do first. Even a cheapo brand may get you to the post screen. If you try to rma the board, examine carefully for any burnt marks, and just tell them it won't post. But if the smell persists around the board, chances are asus will deny the rma anyway.