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Built a new PC; had issues with case fans and not booting

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April 30, 2012 4:17:56 PM

:(  Hey guys, I have a question for everyone regarding my recently built PC:

I put my new PC together and I had all the case fans attached to my PSU and they were all working, so I went to power on the MOBO and the display didn't work, so then I realized I forgot to plug in the 2nd power cable into the MOBO (near the CPU). Once I did this, the PC turned on fine, everything worked so I installed Windows 7, and then powered it down and plugged in the side case fan (with a little 3 prong plugin) into a molex cable I had laying up top, went to power on the PC and it wouldn't boot.

So here I was ,completely stumped, I unplugged the side case fan, switched off the PSU, turned it back on and then the PC booted up. I've had it running for 3 days now (with reboots in between) and my CPU temps are fine (23C idle, 39C load) and my GPU's are also running cool (34C idle, 65C load),

My question is this: should I plug in all the fans into the MOBO? This was my plan after work today, but it just doesn't make sense why it would not power on with that side fan plugged in, is it perhaps because I mis-managed a cable and it's looping back which is causing it not to boot?

System specs are:

HAF 932 Cooler Master Case
212 Cool master CPU fan
i5 2500k sandy bridge
GTX 570 x2 SLI
ASRock P67 Extreme4 Gen3
16GB DDR3 2133 mhz
120GB SSD
1TB HDD
April 30, 2012 5:00:30 PM

what psu?

sounds like something is defective in the fan, psu or any adapter you are using between psu and fan. Try a different molex cable.
April 30, 2012 5:10:51 PM

slicedtoad said:
what psu?

sounds like something is defective in the fan, psu or any adapter you are using between psu and fan. Try a different molex cable.


It's the CORSAIR Professional Series HX850 (850W). Yeah, I'll try plugging it directly into the MOBO tonight and see if that fixes it.

I have a feeling it's the cable, because everything else has worked fine for 3 days now; I just wanted to see if anybody had an issue like this. I also had that side fan working before in my tests but then later down the road it stopped when I connected it to this one molex cable.
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a c 78 B Homebuilt system
April 30, 2012 5:17:06 PM

Are you plugging this fan in while the PSU is connected to the wall outlet?
April 30, 2012 5:26:34 PM

Raiddinn said:
Are you plugging this fan in while the PSU is connected to the wall outlet?


I believe when I did it that the PC was off, but yes it was plugged in.
a b B Homebuilt system
April 30, 2012 5:26:36 PM

always plug cable in the computer when the power is off
April 30, 2012 5:34:49 PM

yeah, make sure non of the pins are badly bent as well. If the are squished and shorting, this would cause the PSU to shut off before damaging itself.
April 30, 2012 5:43:54 PM

slicedtoad said:
yeah, make sure non of the pins are badly bent as well. If the are squished and shorting, this would cause the PSU to shut off before damaging itself.



Thanks for the advice! Would it be wise to plug in my case fans onto the motherboard (CHA_FAN) slots and I planned to plug the side case fan into the PWR_FAN slot near the CPU.
a b B Homebuilt system
April 30, 2012 5:46:48 PM

if they are 3 pins ones to the motherboard but if connector got only 2 pins to ths psu
April 30, 2012 5:47:52 PM

scout_03 said:
if they are 3 pins ones to the motherboard but if connector got only 2 pins to ths psu


Kk, will try this at home tonight and report back.
a c 78 B Homebuilt system
May 1, 2012 1:32:53 PM

I didn't ask you if the computer was off.

I asked you if the plug was connected between the wall outlet and the computer.
May 1, 2012 1:37:10 PM

Raiddinn said:
I didn't ask you if the computer was off.

I asked you if the plug was connected between the wall outlet and the computer.


Quote:
I believe when I did it that the PC was off, but yes it was plugged in.


I got it working by unplugging the PC and disconnecting the 2 connectors to the mobo and then plugging them back in.
a c 78 B Homebuilt system
May 1, 2012 2:01:16 PM

My bad, I guess I missed that part.

Anyway, is the problem gone now?
May 1, 2012 2:14:38 PM

Raiddinn said:
My bad, I guess I missed that part.

Anyway, is the problem gone now?


Yep! I plugged in 2 case into the mobo, the other 2 into the PSU, "reset" the mobo and it's been working perfectly. Thanks for all the help guys :wahoo: 
a c 78 B Homebuilt system
May 1, 2012 2:33:39 PM

In the future, any time you want to open the case, I would suggest you disconnect the power cord. It is just a general best practice to do so.

When the cord is plugged in, even if the computer is off, there is still power flowing through the cable. That allows the power button to turn the computer on, for instance.

When modifications are made while that power is flowing, strange things can happen that wouldn't otherwise. Components being damaged is one possibility, thankfully it doesn't appear to have happened in your case.
May 1, 2012 4:50:16 PM

^i prefer just switching the swtich on the psu to off. This is so i can continue to use the PSU as a ground (by touching the casing every now and then) without any power flow.
a b B Homebuilt system
May 2, 2012 1:24:56 AM

when i play in the computer always on plug from wall outlet for safety
a c 78 B Homebuilt system
May 2, 2012 5:23:24 PM

You can already touch the case of either the PC or the PSU to ground yourself. It doesn't have to be connected to the wall for that.

You may have like 1% better grounding if the cord is plugged in, but then you have to remember to turn the power button off every time because if you forget to flip the switch then you can get problems like the OP had.

If you just get used to severing the physical connection you are maximally protected every time.

It is the best practice to sever the connection for a reason.
May 2, 2012 11:18:36 PM

If the computer is on a carpet or something else that isn't grounded (or if it has rubber feet) it won't ground you by touching the chassis. If it's plugged in, it will completely discharge any static charge you hold.

But if you think you're likely to forget the power switch then it's safer to always unplug it. Damage from static shock is not as serious as it was ten years ago (in my experience anyway) and provided you handle the hardware carefully it shouldn't be too much concern. Plugging hardware in with the power still on is a concern.

Speaking of computer damages...
A guy at my work, today, just burned out a stick of ram by not inserting it all the way before turning the computer on. Don't do that. It makes a funny smell.
a c 78 B Homebuilt system
May 3, 2012 1:03:13 AM

The metal shell of the case can accept as many electrons as you are going to hold in your body unless there is something seriously wrong.

It doesn't matter if they actually flow into planet Earth in this case, because they are out of you and that's the important thing.

I have never heard of anyone doing static damage to their parts if they touched the metal part of the case early and often.
May 3, 2012 1:42:45 AM

ah, I had always thought they had to actually be "grounded". What you're saying makes sense though. Thanks for correcting me, I hate knowing wrong things.
!