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Computer not turning on

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June 27, 2009 9:32:59 PM

hey guys, so heres the scoop:

I took out my motherboard and decided to reapply some thermal compound onto my cpu. After I put everything together again, the computer wouldnt turn on. It worked perfectly before that.

All my cables are in the correct place.

However something strange goes on when i connect my ATX cable HALFWAY in. The fans start to turn on, then shuts down again. It keeps on turning on and off until either I connect the cable all the way in or take the cable completely out.

After trying for a while, the computer decided to turn on, only to turn off after a few seconds.

Any ideas?

More about : computer turning

a b V Motherboard
June 27, 2009 9:39:54 PM

Sounds like the the MB is shorted out. Try unplugging everything except the video card, 1 DIMM RAM and CPU. If the system still shorts out, the MB is likely shorted out to the case. Be sure to use brass risers in all the MB mounting holes and reinstall the MB.
June 27, 2009 10:04:24 PM

i tried what you told me, still aint working. So if my mobo is short circuited, then am i pretty much screwed?
Related resources
June 27, 2009 10:06:26 PM

*oops double post*
a b V Motherboard
June 27, 2009 10:22:52 PM

Gee Badge, do you think he took ALL the brass risers out too?? The question that comes to mind, is he states "something strange goes on when i connect my ATX cable HALFWAY in". Is the power cord STILL attached and on while you're plugging in the power supply to the mother board, youra6? And while we're on a roll, why would you remove the mother board to re-apply heat sink grease? OOPS is correct!
June 27, 2009 10:34:44 PM

Marcellis22 I appluad you. For one wasting your time posting, and two, wasting my time reading your post.

before you start being a little sarcastic, helpless, and insensitive, realize that I took out the mobo, because its hard to take out the heatsink with a case blocking my way.

Please, any helpful suggestions is welcomed
a b V Motherboard
June 28, 2009 12:52:09 AM

Read the next post...
a b V Motherboard
June 28, 2009 1:01:06 AM

You state the fans start to spin up when plugging the "ATX" cable. That seems to me you have the power supply plugged into power and on. Bad combination when plugging in cables. 30 years of computer tech/support doesn't make me helpless, but when dealing with people like you I do become sarcastic and insensitive, removing the motherboard to replace heatsink grease is like pulling the car engine to drain the oil...was the CPU overheating? I suspect not, one of your buddies suggested it would be a good idea! Hire a professional next time!
a c 177 V Motherboard
June 28, 2009 1:50:09 AM

I don't get the whole argument; I usually recommend that you remove the motherboard to install the HSF; you need to see the pin backs to check if they're all properly locked, and that none are cracked or broken. That whole 'spin it up, shut it down' business is often indicative of an overtemp problem; the processor fires up long enough for the BIOS to start controlling the fan, then the thermal trip shuts it down. I have had numerous people swear to me here that they're sure they did the HSF install correctly, and then sheepishly come back to report either a pin loose, unlocked, or cracked... It's not inattention or incompetence, either - there seems to be a contest going on (but I think Intel's system wins hands down with their really crappy 'stock' 775 piece) to see who can design the worst, most impractical way to attach a heatsink! I've tried a few, and, with one exception, they all stank! (The exception: I finally bit the bullet and went to water - have a D-Tek Fuzion, and it came with: an 'x' shaped, threaded, metal backing plate with reinforcing ribs and a molded-on foam rubber insulating pad, and a spring-loaded set of screws with a machined release [not a single &^%$ ^%#@ plastic piece involved!] that lets you get to exactly the correct tension, and then simply turns without tightening further; the drawback - you have to have unimpeded access to the back of the MOBO; I've written D-Tek and told them they should quit wasting their time on water-blocks, and sell mounting systems to every HSF manufacturer!)

IMHO, the best feature of GB's 'ultra-durable' MOBOs (which is, otherwise, a bunch of ditzy marketing hype - '50 degrees C cooler'? - I'm pretty sure that if anything on my MOBO was 50 cooler, there'd be frost forming on it!) is that they'll take enough pressure to get an HSF seated without giving you the ominous feeling that you're a half-ounce of pressure away from a dreadful, fatal snap! Another point to be made is procedure: it's usually easier to 'work your way' around the chip, but, for the best results, you want to do a pair of diagonally opposed pins first, and then finish up with the other two...
June 28, 2009 2:14:33 AM

guys.......jezz

is all connecters checked to be in place ? and down properly and you can't screw the board in without the stand offs anyway.

do a minamal boot basic stuff in prerty much try that.
June 28, 2009 3:05:19 AM

marcellis22 said:
You state the fans start to spin up when plugging the "ATX" cable. That seems to me you have the power supply plugged into power and on. Bad combination when plugging in cables. 30 years of computer tech/support doesn't make me helpless, but when dealing with people like you I do become sarcastic and insensitive, removing the motherboard to replace heatsink grease is like pulling the car engine to drain the oil...was the CPU overheating? I suspect not, one of your buddies suggested it would be a good idea! Hire a professional next time!


That seems to me you have the power supply plugged into power and on.

What do you mean by that sentence. Im a bit confused
a b V Motherboard
June 28, 2009 4:16:34 AM

If the fans spin up when plugging in the "ATX" connector, then you might have the power supply connected to the AC outlet in the wall, which may have provided a power surge to the mother board, possibly toasting it... that's all.
a b V Motherboard
June 28, 2009 4:29:46 AM

Hey, Bilbat and AMG, figure it out on a cost per hour basis, the customer doesn't want to spend a cent more than what he thinks the job MIGHT be worth, but to do the job correctly, it actually costs more. To pull the motherboard to re-seat a CPU heat sink is asinine, learn to do the job like a pro, or get out of the business. Sure it's MUCH easier to do the job with the board out of the case, but does the customer want to pay for the almost hour it takes to do that?
June 28, 2009 6:36:46 AM

marcellis22 said:
If the fans spin up when plugging in the "ATX" connector, then you might have the power supply connected to the AC outlet in the wall, which may have provided a power surge to the mother board, possibly toasting it... that's all.



Well there appears to have no physical damage, no smoke, no burns or anything like that.

I plugged in everything before turning it on. I used a surge protector, i didnt use it from a outlet from the wall
June 28, 2009 4:06:56 PM

youra6 said:
Well there appears to have no physical damage, no smoke, no burns or anything like that.

I plugged in everything before turning it on. I used a surge protector, i didnt use it from a outlet from the wall



What he is questioning is did you have your PSU plugged into a hot outlet? Being a wall outlet or surge protector plugged into a wall outlet or UPS unit... were you were connecting wires that had some charge to it and probably fried something?
a b V Motherboard
June 28, 2009 4:14:31 PM

Breadboard with only the CPU. Short the power pins. If the CPU fan stays on, then you know the motherboard has no short.
June 28, 2009 5:00:39 PM

hundredislandsboy said:
Breadboard with only the CPU. Short the power pins. If the CPU fan stays on, then you know the motherboard has no short.



Sorry, but how do you short the power pins?
June 28, 2009 7:00:51 PM

Not withstanding marcellis's "helpful" posts on this matter.... Yanno, when someone cuts their finger and says "help me... I've cut myself".... Is the help someone is looking for to tell them they should have been more careful or they should have used a knife that wasn't so sharp???? NOOOOO, I think you should help by trying to stop the bleeding and maybe helping to bandage.

Marcellis... if you truly DON'T want to help someone that is obviously "not as smart as you" cuz you obviously know all.... and so shouldn't everyone else too... right?? Then don't bother to post ANYTHING.

Thank you, my lil rant is finished.

OK... youra6, This is what I would do.

1. Remove MB from case, as you did to begin with.
2. Recheck your HSF to see if it might not be seated correctly. Does it appear to be sitting flat on top of the CPU??
3. Remove and reinstall one stick of memory... just one for now and make sure it is seated properly in its slot.
4. Add your video card if your not using an integrated video port.

5. Place your MB and case on your table "non metal of course". Orient them so you can plug the power cables in from the PSU.
6. With the main power cord from the wall outlet disconnected from the wall or power supply, plug the PSU power connector into the MB. The 24 pin power and the 4 or 8 AUX CPU Power plug if your MB uses that. Also and power connector to the video card if your setup uses that as well.

7. Connect a monitor and keyboard.
8. Connect power to the PSU and turn on the monitor.

9. Now short the power switch pins on the MB. As I don't know what MB you have, I can't say exactly what pins to use. Hopefully you made a note where what wires go where when you unhooked everything from the MB header connector.

Anyway, if your sure as to what two pins go to the power switch on the front of your case, just use a small screw driver to temp short the two pins together.

Let me know what you get.....
June 28, 2009 8:13:26 PM

thanks, ill try that tonight
June 28, 2009 8:18:05 PM

the PWR switch pins, it actruly tells you on the mobo and more clearly in the instruction manual. I suppose a paper clip would do or something or screw driver
June 28, 2009 8:44:43 PM

amg answered it, sorry
June 28, 2009 8:58:48 PM

you done it already?:p 
June 29, 2009 1:14:05 AM

lol not yet, i found a forum article that tells me how to short pins. That should help me
a c 177 V Motherboard
June 29, 2009 5:27:22 PM

This really points out to me what an old fart I am; there's a whole generation or two of builders out there who don't have a shoebox full of extra pin jumpers laying around! Back when dinosaurs were using computers, before you could put your lousy modem into your computer (and, probably soon, I'll need to explain what a modem is!), you had to 'shuffle around' a dozen or two shorting jumpers to set its address and interrupt useage; all this stuff has been configured in on-board NVRam or CMOS for so long, that jumpers are museum artifacts!!

Reminds me of the banner my ex put up in the bar where my fortieth birthday party was held: "Put the horses in the wagon; it's all downhill from here!"
June 30, 2009 3:32:18 AM

lol yeah my dad warned me about jumpers, and im like dad.... i dont i have to deal with a whole lot of jumpers anymore.

Shows how old he is, but that was years ago. The last computer he built was in 95 or something
!