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Newly built PC won't start up

Last response: in Systems
June 29, 2010 7:11:17 AM

Hey all, I'm having a problem with the home-built computer I put together today. I followed the instructions in the parts manuals and plugged everything in, and I thought everything was perfect and ready to run. I plugged in the machine and hit the power button, and nothing happened. The only way I can even tell that my computer is actually assembled is because the motherboard LEDs light up when power is flowing to it and when I hit the power button on the computer, it shows a split-second light-up on the power LED then goes back to off. The power supply fan never moves, nor does it light up (I think it's supposed to). I read some articles on troubleshooting this, and they said basically that either the plugs aren't in all the way or that the power supply is dead. I re-plugged everything in, and nothing changed.

What could this possibly be? I want to check every possible solution before changing out the power supply, because I don't think I have a warranty on it any more. I don't have a CD or DVD drive hooked up to it, could that be it? I'll test that after I finish posting this, but other than that, I'm out of ideas.

Let me know what you think.

More about : newly built start

June 29, 2010 7:58:15 AM

If your motherboard light is on; chances are your powersupply is just fine. This sounds like you've simply messed up with the front panel connectors which is pretty common.

Have you double checked that your connectors are not just on the right pins, but the right way around? They normally have a wee triangle for + and nothing for - and the triangle (i think) always points towards the first pin (so if your two power pins are 4 and 6 then the triangle should be at 4).

I hope this helps (if any of it makes sense?)
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June 29, 2010 8:14:42 AM

Update: I know it's not the power supply now. I just connected it to my old machine and it's working fine, and the old power supply is giving the same problem on the new machine. So now I'm going to troubleshoot the connectors, like acer0169 is recommending. Thing is, I only found 3 connectors and the instructions say there's supposed to be 5 or 6. hmm...stay tuned.
June 29, 2010 8:36:39 AM

the motherboard's manual should tell you how the front panel wires should be connected
June 29, 2010 8:36:57 AM

Okay, I tried the front panel connectors and read the manuals to make sure I hooked them up in the right spots, and they're hooked up properly. What else could be wrong? I'm going to read the troubleshooting article while I wait for more ideas...
June 29, 2010 9:01:37 AM

I read the troubleshooting guide and none of those fixes solved it. I re-checked the connections and the CPU fan and everything. There's no loose screws, the components are meant for each other, and so on...but I can't get anything more than a quick flicker of light out of the power on LED and the motherboard LEDs. Maybe I should test the motherboard next?
a c 122 B Homebuilt system
June 29, 2010 1:25:30 PM

acer0169 said:
If your motherboard light is on; chances are your powersupply is just fine.

Not true. The motherboard LED is powered by the small (10 - 15 watt) standby power supply. Except for input power and a common PSU enclosure, the standby power supply is completely separate from the main section that actually provides operating power to the PC.
June 29, 2010 6:06:25 PM

This problem has NOT been solved, guys. Please help, I spent all last night troubleshooting and my machine's still dead on my floor. The power supply is fine, it's running my old computer. The old power supply that works fine gives the same flicker of the power LED and the motherboard LEDs stay on when power is flowing to them, but other than that, there's no sign of life in it.

Best solution

a b B Homebuilt system
June 29, 2010 6:44:26 PM

A few ideas:

#1. is your power supply rated for your new systems power requirements?

#2. are you sure that you have all of the power cables hooked up to your motherboard? There can be quite a few of these! (i've done that before, gives the same issue you describe)

#3. Does your motherboard have an onboard "power on" button? If yes, try to see if this will boot the system. If no, do you have the power switch cabling hooked up to the motherboard? Could the switch be broken/wire broken internally?


Seems to me that its either a broken/impropperly hooked up switch or you forgot to connect all the power cables. Your motherboard should have come with a picture with lablels. Make sure you have them all.
June 29, 2010 11:06:29 PM

jsc said:
Not true. The motherboard LED is powered by the small (10 - 15 watt) standby power supply. Except for input power and a common PSU enclosure, the standby power supply is completely separate from the main section that actually provides operating power to the PC.

Ahh I stand corrected!
Always happy to learn something new.

I've always thought that teh LED light took the same power as the CPU (so either the 20 pin, 20+4 pin or 4/8 pin cpu power connector) so I thought that was a good sign.

Back on subject.. even if you think you've got your front panel connectors in the right way, have you tried plugging your power switch in the other way round?
June 29, 2010 11:42:44 PM

Hi Mate,

You really want to strip to to the bare bones, which are

CPU (Connect your 4 pin and cpu fan)
Graphics Card(if on board use on board) and monitor

Dont connect anything else, no usbs, not even the power button connector

At this point you should clear the CMOS, thats a jumper, switch it for about 10 seconds then put it back to original position.

To start your computer use a screwdriver and short the 2 pins that are used for the power, no messing around!!

Try it first without the RAM, you should get some kind of beeping from your speaker, if you dont then I would say your mobos not doing what its suppose to.

If it beeps then your in business.

Try your single stick of ram in the second slot away from CPU, when sarted you should get a post, which is something on the screen.

If not try it again this time in the slot nearest your CPU.

Good luck!!!
June 30, 2010 1:23:14 AM

you could try using a "mainboard testing set" from like a micro center or other pc store, comes with power push button, reset push button, power led, hdd led, and a speaker

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July 1, 2010 5:11:30 AM

Good news, guys. I found out the problem through sheer trial and error efforts (which took me about 14 hours, sad to say). In case anyone ever asks you again or you're just curious, the problem was that I had the case fans plugged into both the power supply and the "CHA_FAN1" slot on the motherboard. All I had to do was remove the motherboard hook-up and everything worked fine. I knew it would be ridiculously hard to find out a stupidly simple solution. :p  So next time some noob like me has this problem, let them know that the case fans CANNOT be plugged into BOTH the power supply and the motherboard, but can be plugged into either one separately. Oi! That was quite a learning experience!
July 8, 2010 12:21:30 AM

Best answer selected by FreyjasChosen.
July 8, 2010 6:37:43 PM

that makes sense

you'll have to plug it into your motherboard if you want to have of control of it, it'll run on max speed if plugged directly to PSU