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The switch on my PSU turns on my computer but not the case switch

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October 31, 2012 4:23:00 PM

Hello,

I have a possible case wiring problem or grounding issue, from what I can tell.

My system is:

Intel i5 3570K Ivy Bridge

ASUS P8Z77-V LK Z77 LGA 1155 R

G.SKILL Ripjaws Series 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model F3-12800CL9D-8GBRL

OCZ ModXStream Pro 600W Modular High Performance Power Supply compatible with Intel Sandybridge Core i3 i5 i7 and AMD Phenom

SAPPHIRE Radeon HD 6850 1GB 256-bit GDDR5 PCI Express 2.1 x16 HDCP Ready CrossFireX Support Video Card with Eyefinity (100315L )

Western Digital WD Blue WD5000AAKX 500GB 7200 RPM 16MB Cache SATA 6.0Gb/s 3.5" Internal Hard Drive -Bare Drive

ASUS 24X DVD Burner

COOLER MASTER Storm Scout SGC-2000-KKN1-GP Black Steel / Plastic ATX Mid Tower Computer Case

The problem is as follows. When I first plug in the PSU to the wall and switch the PSU on, the computer starts up, without me pushing the case power switch. The case power switch then does not shut off the computer. If I switch the PSU off, wait 10-15 seconds, leaving the PSU cable plugged in, then turn back on the PSU, the computer does not start up, nor does the case power switch turn the computer on.

The power switch on my case has successfully started up another computer, and so has my power supply.

I have had so many problems with my first build...two RMA's with Newegg, for starters. I'm hoping someone can trouble shoot this.

Thanks,
Alex
October 31, 2012 5:45:17 PM

recheck the wiring diagrams for mobo and case against each other.
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October 31, 2012 7:31:27 PM

with a volt meter if you have one. set it to ohm's and take the on switch of the case and open and close it. with the switch open you should get a very high air reading. with it closed it should be 0 or close to it. the on switch on a mb is turned on by low voltage flowing across the two on switch pins. i seen on some cases the vendor uses a small daughter board between the on switch and the mb. some time the on switch cable is lose or on wrong or the daught card goes bad. also try swapping the (+) and (-) of the on switch cable. the switch is only going to work right if connected right.
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October 31, 2012 7:55:24 PM

smorizio said:
with a volt meter if you have one. set it to ohm's and take the on switch of the case and open and close it. with the switch open you should get a very high air reading. with it closed it should be 0 or close to it. the on switch on a mb is turned on by low voltage flowing across the two on switch pins. i seen on some cases the vendor uses a small daughter board between the on switch and the mb. some time the on switch cable is lose or on wrong or the daught card goes bad. also try swapping the (+) and (-) of the on switch cable. the switch is only going to work right if connected right.


Given that my power switch on my case has started up another system successfully, wouldn't that rule out having to use a volt meter or the switch having a bad daughter card?
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October 31, 2012 7:55:25 PM

AntiZig said:
recheck the wiring diagrams for mobo and case against each other.


The wiring is correct as per the MOBO diagram. Any other suggestions?
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October 31, 2012 8:13:07 PM

Something is screwy, your machine shouldn't be instantly receiving a start-up signal as soon as the PSU is turned on. Are you using the Q-Connector for the front panel and case plugs? I would first try removing all front panel/case plugs (or just your Q-connector) and then see if flipping the PSU on starts the PC. If it does not, try shorting the case power button pins and see if it will then start.
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October 31, 2012 8:18:46 PM

Has a loose screw or other foreign object gotten on or under the mobo, possibly shorting something? You say the switch has powered another board; presumably in that same case. So, when you removed the old mobo and installed the current one, did you make sure there are standoffs ONLY where there are screws, or did you leave one somewhere there is no screw?

Edit: The power LED wires will have a (+) and a (-) on them; the power SWITCH wires will not be so marked (polarity doesn't matter on a switch). Any chance you have these wire pairs reversed?
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October 31, 2012 8:24:38 PM

Onus said:
Has a loose screw or other foreign object gotten on or under the mobo, possibly shorting something? You say the switch has powered another board; presumably in that same case. So, when you removed the old mobo and installed the current one, did you make sure there are standoffs ONLY where there are screws, or did you leave one somewhere there is no screw?

Edit: The power LED wires will have a (+) and a (-) on them; the power SWITCH wires will not be so marked (polarity doesn't matter on a switch). Any chance you have these wire pairs reversed?


I actually connected the existing case wiring to another motherboard that was seated in a different case. Tonight I am taking the motherboard out and trying to start up the whole system in a clean cardboard box. I do not believe there are any other foreign standoffs in the case, but I will be thoroughly checking tonight.
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October 31, 2012 8:29:54 PM

As a general question to make me feel better about my large quantity of expensive computer components that are essentially useless to me right now, what can be ruled out as not being the problem? Bear in mind that I have successfully gotten to the BIOS, poked around, monitored temperatures, fan speeds, and voltages and things seem to be normal (from what I can tell). Once the system has power, things appear to be alright. But obviously the power switch issue is not good at all.
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October 31, 2012 8:35:49 PM

Sounds like a MOBO short, if your going to try bread boarding that could confirm or deny whether a short is the issue. Your MOBO is sending the power on signal regardless of whether it should or not, makes me think that the switch is stuck on, which would indicate a short.
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October 31, 2012 8:37:10 PM

there must be a short with the front panel connectors. or part of the power button could be stuck causing the fault. most likely a case problem.
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October 31, 2012 8:37:49 PM

chugot9218 said:
Sounds like a MOBO short, if your going to try bread boarding that could confirm or deny whether a short is the issue. Your MOBO is sending the power on signal regardless of whether it should or not, makes me think that the switch is stuck on, which would indicate a short.

So from what I understand, best case scenario is that there is possibly something touching the motherboard that is grounding it and causing it to behave this way. Worst case scenario is there is something inherently wrong with my motherboard? If that is the case than Newegg can just bite it. It will be my second RMA of a motherboard with this build.
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October 31, 2012 8:40:22 PM

LordTsar said:
there must be a short with the front panel connectors. or part of the power button could be stuck causing the fault. most likely a case problem.

But my case has successfully started up a completely different system. I connected all of the case wiring to a different motherboard seated in a different case. Do you think the case is still at fault?
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October 31, 2012 8:46:49 PM

Yeah, sounds like your case is good to go, I suspect the MOBO still, but bread boarding it would confirm.

Your conclusions a post or two up are correct (in my opinion).
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October 31, 2012 8:51:20 PM

chugot9218 said:
Yeah, sounds like your case is good to go, I suspect the MOBO still, but bread boarding it would confirm.

So tonight I am going to try the following trouble shooting:

Starting up another system, again, using my case wiring.

Removing the motherboard, breadboxing everything, and trying to start up the system.

Starting up my system in its case with another case's power switch/wiring.

I will do these in this order most likely. Does that sound like a good way to proceed?
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October 31, 2012 8:53:29 PM

Also, could there be anything wrong with my power supply?
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Best solution

October 31, 2012 8:53:34 PM

I would just bread-board right away, did you ever try starting it up without any front panel plugs in?

*edit* I was thinking it may be a PSU issue, but it is the MOBO that controls whether the PC turns on or off, so if the PSU was faulty it would somehow have to bypass the MOBO power switch, which I don't think is likely *edit*
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October 31, 2012 10:12:50 PM

If breadboarding outside the case works, I would run a strip of electrical tape around the edges of your mobo, especially the back edge, where it is possible a slot cover or other metal is contacting a trace within the mobo's layers. Don't scoff; I've had this happen to me personally, and this was a cure.
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October 31, 2012 10:31:40 PM

"did you ever try starting it up without any front panel plugs in?"

^ This. Before you go to all the trouble of removing your motherboard, try just disconnecting ALL of the front panel connections and power it on using a screwdriver to connect the two Power Switch pins on the motherboard.

Also verify that the diagram in the manual actually matches the pin labels on the motherboard itself. I've seen instances where they don't, and your problem could be as simple as having your power button hooked up to the wrong pins because of a minor discrepancy like that.
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October 31, 2012 11:31:19 PM

Best answer selected by aigram.
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November 1, 2012 2:08:01 PM

So you've figured it out? what was it?
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November 1, 2012 4:22:57 PM

It turns out that the PSU was somehow the problem. It was continuously supplying power. I went for broke and tried using a friend's power supply, and now everything powers up, except for my GPU. So, now on to more hardware trouble shooting! Check for a new thread...:/
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