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New PSU, no boot.

Hi everyone,
Over the past few weeks I had been having a problem with my machine. It usually stays on most of the time, but on the odd occasion I actually powered it down (shut down instead of reboot) it wouldn't restart for a period of time, maybe 5 mins or so. Eventually, earlier this week, it wouldn't turn back on at all. I got in behind it to check some things and noticed a horrible smell, and traced the smell to the PSU (Antec NEO480).

Pinpointing that as my problem, I went and purchased a Corsair 500CX PSU, and installed it with everything as it was before. When everything was plugged in, I flicked the switch on the back of the PSU. Every fan in the case came on full, but nothing else happened. No output to monitor, no reaction from the case switch, just all fans on full blast.

I've tried a couple things (removing the case switch plug from mobo, d/c the 4pin power from mobo, d/cing peripherals down to none) and it does the same thing every time.

What could be wrong? My gut is telling me that perhaps my mobo has been compromised also and I'll need a new one, but is there any sure way to tell? I'd rather be 100% before I go get another piece of hardware.

Thanks for any help you can provide.

phuser
12 answers Last reply Best Answer
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  1. Is it powering on well, no beeps ?
    Make sure you connected all appropriate wires-
  2. 55Range said:
    Is it powering on well, no beeps ?
    Make sure you connected all appropriate wires-


    No, it's not powering on well. Only the fans come on, no beeps, no booting, nothing to monitor, and all when the PSU switch is flicked, not the case switch. Everything is connected properly.
  3. Something do to with wires- check all connections, check manual to see if you connected properly-
  4. 55Range said:
    Something do to with wires- check all connections, check manual to see if you connected properly-


    Everything is connected properly. Nothing from the mobo was disconnected except for the connections from the old PSU, which were the 24 pin connector and the 4 pin connector

    The only other things disconnected were the power to the video card, the sata power cables to 2 HDDs, sata power to my dvd drive and fan connections. They are all connected as they were before.

    The issue is that it is starting all the fans when the PSU switch is turned on. It shouldn't be doing anything until the case switch is pushed.
  5. The same thing happened to me on one of my machines : PSU works with other computers but not mine

    I really tried everything and after a while I found the answer : The original PSU had 3 12v rails. The ones I tried had only 1 12v rail. Then I tried an Antec that had multiple 12v rails and guess what...it worked !

    Corsair PSUs have only 1 12v rail.

    So the problem you have comes from your motherboard...It's really a pain in the ***. I don't know how many hours I passed trying to figure out what the hell the problem was. I tried 2 different cooler master silent pro gold 1000w, then a Corsair AX1200 (which I kept for my main build) and finally used an Antec True Power Quattro 1000w (that one worked). For each PSU, I tested the voltage/ground on each pin. Well, let me tell you that when I found the solution, I was really pissed. Also, there's absolutly no information about that subject on the internet.

    Good luck,
    al360ex
  6. You know, I wondered about that when I purchased this new PSU. I told the guy what I had before and asked if this one was compatible. He said yes, and seemed more concerned about the 4pin power connector (vs 8) than anything else. When I checked the specs on both PSUs (old and new) when I got home I noticed that the corsair only had 1 +12v rail and my old Antec one had 2 +12v.

    Should I take it back and get a different one then? I'd be glad to hear it wasn't my mobo that's screwed up. I thought maybe my old PSU frying had done something to my mobo.
  7. Well try, i think its the best option -
  8. al360ex said:
    The same thing happened to me on one of my machines : PSU works with other computers but not mine

    I really tried everything and after a while I found the answer : The original PSU had 3 12v rails. The ones I tried had only 1 12v rail. Then I tried an Antec that had multiple 12v rails and guess what...it worked !

    Corsair PSUs have only 1 12v rail.

    So the problem you have comes from your motherboard...It's really a pain in the ***. I don't know how many hours I passed trying to figure out what the hell the problem was. I tried 2 different cooler master silent pro gold 1000w, then a Corsair AX1200 (which I kept for my main build) and finally used an Antec True Power Quattro 1000w (that one worked). For each PSU, I tested the voltage/ground on each pin. Well, let me tell you that when I found the solution, I was really pissed. Also, there's absolutly no information about that subject on the internet.

    Good luck,
    al360ex



    Well, I took back the Corsair and exchanged it for an OCZ with 2 +12v rails, came home, installed, and same thing is still happening. PSU power switch on, all fans come on, nothing to monitor, etc. No beeps or anything. Safe to assume my mobo has been compromised? Anything else I can try?
  9. It really does sound like your mobo is damaged.
  10. Best answer
    Yes, that sounds like a dead motherboard to me too.

    Sorry !
  11. O o, Yes, does look like a mobo fail -
  12. Best answer selected by phuser.
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