PSU cutting off almost instantly after powering up?!

C

CrashGawker

Gawd
Joined
May 30, 2002
Messages
630
I've been saying for years "one of these days I'm going to save up enough money to build a new system all at once. Completely new parts, all ordered and gathered together at one time and assembled together at the same time. No waiting for parts, no recycling parts, just a new computer with as few hassles as humanly possible." I was trying to save up ut things got the jump on me and I built my new system without being able to get everything and it's being a real SOB.

Found the trouble with me system not reacting in any way to my power button...the lead coming off the switch had somehow been broken so pushing the button effectively did diddly. Now I have a NEW problem...my PSU kicks on for less than a second (the PSU fan lights up and spins for a second and the other fans in the system spin up) but almost instantly cuts off. This is the behavior the PSU is exhibiting when hooked up to and powered up through the motherboard (Asus K8N-E Deluxe). When hot wiring the PSU alone using the jumper between green and ground the PSU spins up and runs happily with no issues.

I've scalped the system down to bare bones (CPU, PSU, RAM, MOBO, OS DRIVE, COOLING) and there's no change. What sort of problems could cause this sort of reaction so I can start trying to figure out what the culprit is.
 
That also happened to me on my older comp after I moved it to a different floor in my home after a Starcraft LAN with my friends. All I had to do was just pull out the mobo connector, blow some dust out of it and reseat it. Problem solved.

Just for the heck of it, here's another time I screwed up on the PSU. This happened to my newer comp, with some fancy schmancy P4 connector. I didn't know about it so I left it unplugged, and while the fans and stuff spun up, it wouldn't POST. Then I plug one of the 4-pin plugs in (OCZ Powerstream so it's got two, where one of they attach together to form an EPS12 connector) and it was the wrong one, so my PC won't even turn on. Plug the other one in, and it POSTs!

So yeah, good luck on that.
 
Yeah...well I didn't try blowing on it...but during the process of trying to figure it out I pulled the ATX power cable off the mobo to hot wire the PSU to make sure it wasn't dead and then plugged it back into the motherboard without any change. I'll go try blowing it clear and get back on here if it makes a difference.

Also my two 4 pin power connectors are keyed using square pins and the ones with the corners missing so only one of them can be plugged into the motherboard. It's plugged in.
 
There are only two possibilities here: It's either the mobo or the PSU. Swap these two items out and see if you can isolate the problem further (if not them as the culprit).
 
Actually I found the culprit last night but went to bed rather than staying up to write a post...and believe it or not it was neither the motherboard nor the PSU. I had turned off the CCFL switches in back of the computer (PCI slot switches x 2) while I was in the guts of the machine just cause I didn't see any reason for them to be on. Well for whatever reason I turned them back on and the problem stopped. Turned them off again and the problem returned, turned them on and the system booted right up.

Narrowed it down to the upper switch used to control the pair of 4 inch cathodes in the top half of the case. I have no idea why the switches would cause the system to behave this way but once I get the money together to rewire the whole system and sleeve/hide the wiring those switches are OUTTA HERE!!!
 
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