System Won't Boot

[Riboflavin]

Just finished puting together a new system, and when I hit the power button, the lights on the front of the case flash for just a second, then nothing happens. No fans come on, not even the power supply. If I hit the power button again I can't get the lights to flash unless I unplug it and plug it in again, then it will flash once more. I would really appreciate any ideas you guys have, it sounds kinda like a short but I don't really know what I am talking about. The power switch is plugged into the right pins on the MB and both power connecters are in the MB.

Here is a list of parts:

Case
2gig value ram
Mobo
Video
Processor
HDD

 

[blacklabelrum]

Hey, I’ve just experienced that same thing with a system I just got to repair this afternoon! When turned on, the power led comes on for a second and the PSU fan would just start to spin and then everything goes dead. Lol. Anyways, I didn’t get to troubleshoot that system as yet but I think it has something to do with the power supply. I’m going to start work on it tomorrow, so I’ll tell you about my progress. (If any).

 

[Riboflavin]

Thanks, I appreciate it.

For me, the system fan spins about 1/100th of an inch just barely enough to notice. Also, when I unplug it after about 5 seconds it makes a high pitched squeek that sounds kinda like something shutting down.

 

[PC eye]

Chech to make sure you are not grounding out on the chassis and recheck all connections like the four wire plug that goes in near the cpu socket. What make and supply are you using? Is it a 24pin or 20+4pin supply? Also look over the harness from the front panel in case you jumped the wrong pins when plugging those in. The four wire plug left will stall a system right there.

 

[Riboflavin]

Also look over the harness from the front panel in case you jumped the wrong pins when plugging those in. The four wire plug left will stall a system right there.

I'm not sure what you mean by that, can you explain? Thanks

 

[Jet]

My computer always does that when something is not plugged right. Just check all of your connections. If they are all right, unplug all of the fans from your motherboard except your processor fan, and then plug your fans directly into your power supply.

The case fans that came with my computer would make it do that if they were plugged into my motherboard, but my Antec Tricool fans never would mess up.

 

[Riboflavin]

Ok I just played around with it some more. Turns out I had the plug labeled "24 pin only" into the power spot beside the processor. I removed it and plugged in the unlabeled one. It booted up for about 5 seconds, then died.

 

[Riboflavin]

Ok, my motherboard says it has a 24 pin power connector but on the last 4 pins there is a small plastic cover. Does this mean it can run with 20 pins or do I need to remove the small cover? Also, the 4 pin connector I removed from beside the cpu, should that be in the last 4 pins or is there suppost to be an entire 24 pin thing comming from the power supply?

Edit: Ok, I plugged in the extra 4 pin connector to the side of the 20 pin and attached it to the motherboard and the same thing happens. It boots for about 5 seconds and then dies. The the sys fans come on but the power supply fan doesn't turn at all

 

[Jet]

There should be a full 24 (2x12) pin power plug that goes in to the motherboard, in addition to another 4 (2x2) pin plug that goes in near the CPU.

 

[Riboflavin]

There should be a full 24 (2x12) pin power plug that goes in to the motherboard, in addition to another 4 (2x2) pin plug that goes in near the CPU.

Ok, well what I have comming off of my power supply is a 10x2 which fits into the main mb power slot (though there are an extra 4 holes with a plastic cover over them at the end) and then an unlabeled 2x2 which I plugged into the cpu power slot and then a 2x2 that says "For 24 pin mobos only"

 

[StrangleHold]

Plug the 20 pin power connector and the 4 pin one marked for 24 pin mobos only into the 24 connector togather and the single 4 pin power connector into the CPU 4 pin connector

 

[Riboflavin]

Plug the 20 pin power connector and the 4 pin one marked for 24 pin mobos only into the 24 connector togather and the single 4 pin power connector into the CPU 4 pin connector

I did that and it still does the 5 seconds on and right about when it sounds like its about at full power it shuts off.

 

[shanesmith8]

try switching that switch on the back of your power supply to make it run more power. I had to do that, mine would turn on and off then I switched that, runs fine. Monitor just wont go.

 

[Riboflavin]

try switching that switch on the back of your power supply to make it run more power. I had to do that, mine would turn on and off then I switched that, runs fine. Monitor just wont go.

Ugh, switching it to 240 volts in the US would be a bad idea.

 

[PC eye]

Ugh, switching it to 240 volts in the US would be a bad idea.

That's for sure. The supply mode there would be underpowered by the outlet. In Europe you will find 240v far more common. That's why you have the option between the two positions. Your problem is either with the connections or the board itself. The model board there requires all 20+4pins seen on the main connector. You were getting confused a little there apparently.

Recheck the wiring from the front panel if you haven't done that. It only takes one of the two power button wires to be found on another pin so when you turn on the breaker for the supply the drive lights flash for a second. When slapping the latest case together one of the two wires came up and off. When the supply's breaker switch was turned on the drive lights flashed for a split second with no go. As soon I spotted the pair lifted up and one off of the pin completely I said "ahhh son of..." pushed them down on and the system fired right up! Something simple but you can overlook just one thing and... ?

 

[Riboflavin]

Just double checked all the front pannel stuff, its all in the right place

The only thing that is weird is when it boots up, the rear power supply fan doesnt spin. The front one does and so do all the system fans but not that back one. The after about 5 seconds it dies.

 

[PC eye]

I don't like that one bit. The supply could be the actual problem. Do you have another one you can try to see if that's problem? You may only be seeing a limited output that's just enough for the fans alone.

 

[Riboflavin]

Here is something interesting, the 24 pin connector seems to have one pin missing?

 

[PC eye]

That's done intentionally for the one way fit to insure the correct voltages are going to the correct pins in the main connector.

 

[StrangleHold]

That's done intentionally for the one way fit to insure the correct voltages are going to the correct pins in the main connector.

Wrong again, if you have really looked at a power connector the top edges are cut at a angle the bottom is square, you cant plug it in wrong and a missing pin will not stop you from plugging something in, if you had a pin where there is no hole that would stop you but that is not the case here!! Its a extra ground that some power supplys have and some dont!