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Is this a dead PSU or dead MoBo?

post #1 of 6
Thread Starter 
Alright so for the past month I've been piece-mealing together a new computer.
I've got it to the point where I am able to press the power button to turn it on so I thought I would turn it on to see if everything was working like it's supposed to so far and at that point it turns on and then turns off in less than 1 second. I guess you can say that it flickers on then off once.You can even hear the flicker sound coming from the PSU. After that, to try and turn it on again I have to Unplug the power cable and plug it back in or switch off the PSU power switch and then switch it back on. Once I do that and press the power button, It does the same thing over again. What could be causing this?

MY SPECS:
Motherboard: Asus M4A87TD EVO
CPU/Processor: AMD Phenom II x4 925
Graphics Card: Sapphire Radeon HD 5750 Vapor-X 1GB
RAM: Corsair XMS3 4GB DDR3 (ONE stick)
PSU: Coolermaster GX series 650w

I've tried taking the Graphics card and the RAM stick out; I get the same result.
The motherboard light stays on the entire time even though the PC itself doesn't.
And if this helps at all, I put my ear up to the PSU to make sure everything was alright and it seems to be making a tiny slight electric buzzing sound, even when the power switch is turned off. The only way it stops is by unplugging the power cable. It could be meant to do that but whatever.

Keep in mind, I haven't placed the HDD or the DVD drive in the case yet. Do I have to have these in the case to turn it on? I heard that some motherboards require the Hard drive to be plugged in and in the case for the thing to boot. Is that true? I made sure all cable and plugs were plugged in securely, but I can't seem to find the problem. Everything was brand new when I bought it; nothing was used already! Need anymore information? Just say so.

UPDATE:
Not one fan comes on. The computer turns right back off before any of the fans are able to power on. The RAM is in the very first slot. (The one closest to the CPU fan/heatsink.) I tried taking taking everything out of the case but to no avail. Once again checked all the wires and made sure they were connected in which they were. I've asked all around the internet about this and everybody says it's the PSU, but a few people said it could be the motherboard.
Edited by boro iz rich - 5/14/11 at 8:46am
My System
(13 items)
 
  
CPUMotherboardGraphicsRAM
Phenom II x4 925 Asus M4A87TD EVO Sapphire Radeon HD 5750 Vapor-X 1GB 4GB 
Hard DriveOSPowerCase
400GB (two HDDs) Windows XP (LOL) Coolermaster GX series 650w NZXT Gamma Classic Series 
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My System
(13 items)
 
  
CPUMotherboardGraphicsRAM
Phenom II x4 925 Asus M4A87TD EVO Sapphire Radeon HD 5750 Vapor-X 1GB 4GB 
Hard DriveOSPowerCase
400GB (two HDDs) Windows XP (LOL) Coolermaster GX series 650w NZXT Gamma Classic Series 
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post #2 of 6
I am pretty sure there should be just a single green wire on the 24 pin connector that you can then short to any of the black(ground) wires on the same 24 pin connector. This will turn on the psu and you can then see if it stays on.

At which point, just connect it to the motherboard and nothing else, then the cpu, then the memory, etc etc.


Info here for the green wire(pin 16), courtesy of duckie.
Edited by joemaniaci - 5/13/11 at 11:25pm
I Love Cheese
(13 items)
 
  
CPUMotherboardGraphicsRAM
2600k @ 3.4 Asus P8P67 Basic XFX 5970 2 gig Black Edition 2x 4 gig DDR 1600 G-Skill 
Hard DriveOSMonitorPower
2x500 gig WD Vista Ultimate 64-bit Dual 25" Hannspree LCD CM 750 Watt 
CaseMouse
Rosewill THOR Logitech Trackball 
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I Love Cheese
(13 items)
 
  
CPUMotherboardGraphicsRAM
2600k @ 3.4 Asus P8P67 Basic XFX 5970 2 gig Black Edition 2x 4 gig DDR 1600 G-Skill 
Hard DriveOSMonitorPower
2x500 gig WD Vista Ultimate 64-bit Dual 25" Hannspree LCD CM 750 Watt 
CaseMouse
Rosewill THOR Logitech Trackball 
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post #3 of 6
look for a short somewhere. Check of nothing of the mobo is making contact with the case. Try and remove the mobo from the case and then test it.
Try and switch it on without the hdd aswell. So basically start by using the minimum components eg 1 ram stick no hdd etc etc to see if it stays on with out switching off again. Then add piece by piece till it happens again. But ill try testing it out of the case first and make sure your cooler are seated properly and your cpu is getting enough cooling
Edited by Spooony - 5/14/11 at 7:59am
post #4 of 6
Do the motherboard/CPU fans stay on?
Do your case fans stay on?
Or do they cycle on and off?
Do they spin at all?
What slot do you have your 1 RAM stick?

After disonnecting power plug and plugging it back in does the humming sound return? Can you localize the hum to the PSU fan? Noise from PSU is of concern. Any charred odor from PSU fan?
post #5 of 6
Thread Starter 
SOLVED!

Turns out that nothing was defective and I didn't have to return anything. One of the cables coming from the PSU was somehow connected to the motherboard when it wasn't supposed to be. Hot damn!
Edited by boro iz rich - 5/15/11 at 5:03pm
My System
(13 items)
 
  
CPUMotherboardGraphicsRAM
Phenom II x4 925 Asus M4A87TD EVO Sapphire Radeon HD 5750 Vapor-X 1GB 4GB 
Hard DriveOSPowerCase
400GB (two HDDs) Windows XP (LOL) Coolermaster GX series 650w NZXT Gamma Classic Series 
  hide details  
Reply
My System
(13 items)
 
  
CPUMotherboardGraphicsRAM
Phenom II x4 925 Asus M4A87TD EVO Sapphire Radeon HD 5750 Vapor-X 1GB 4GB 
Hard DriveOSPowerCase
400GB (two HDDs) Windows XP (LOL) Coolermaster GX series 650w NZXT Gamma Classic Series 
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Reply
post #6 of 6
For future reference, this problem is 99% of the time caused by a short circuit of some kind. In this case, you had a cable plugged in where it was not supposed to be plugged, probably the pin-out was reversed vs. what was expected, causing the short-circuit protection to kick in.

Another very common reason for this is putting in the mobo into the tray and forgetting the standoffs (yes I've done it) or something foreign being stuck into one of the peripheral ports in the back (like you forgot to replace the generic backplate that came w/the case with the proper one that came w/your mobo).

Another possibility is cabling where they mixed up the black and red wires somewhere (rare, but not impossible). Or components themselves can just be 'bad' in the sense that they cause a short. HD's are the most likely culprit but it can happen w/any component really.

Glad you got it sorted in any case
    
CPUMotherboardGraphicsRAM
xeon X5675 6-core @ 4.1ghz (1.29v, 20x205 +ht ) rampage iii extreme msi rx470 gaming X (the $159 budget king) 3 x 2gb corsair xms3 pc12800 (9-9-9-24-1T@1600MHz) 
Hard DriveOptical DriveCoolingOS
hynix 250gb ssd (boot), 2tb deskstar (apps),1tb... plextor px-712sa - still the best optical drive... corsair h8o v2 aio W10 home 
MonitorPowerCaseAudio
asus vw266h 25.5" (1920x1200) abs sl (enermax revolution) * single 70A rail 850w silverstone rv-03 XFi Titanium 
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CPUMotherboardGraphicsRAM
xeon X5675 6-core @ 4.1ghz (1.29v, 20x205 +ht ) rampage iii extreme msi rx470 gaming X (the $159 budget king) 3 x 2gb corsair xms3 pc12800 (9-9-9-24-1T@1600MHz) 
Hard DriveOptical DriveCoolingOS
hynix 250gb ssd (boot), 2tb deskstar (apps),1tb... plextor px-712sa - still the best optical drive... corsair h8o v2 aio W10 home 
MonitorPowerCaseAudio
asus vw266h 25.5" (1920x1200) abs sl (enermax revolution) * single 70A rail 850w silverstone rv-03 XFi Titanium 
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