Computer only turns on when CPU is removed

[more123]

Hi,
I am having a problem with an Acer desktop PC.
Specs: It has a Phenom II Quad core CPU, and an Acer branded mother board, a confirmed working stick of ram.
Problem: Computer turned on ok first time logged in Windows .. etc. Now, it went to sleep after like 10 minutes of inactivity but after around 15-20 minutes of it sleeping it shut off. After it was shuts off I tried to turn it on by pressing the power button, everything turns on for a split second and then off again. After opening the case I removed all connectors accept the fan & PSU connectors from the motherboard and I discovered that the computer will actually turn on when either the P2 connector is NOT plugged in or when the CPU is completely removed.
Things I tried:
1. Removed Video card and connected the monitor to integrated vga, same problem.
2. Removed all ram then installed a confirmed working stick of ram, same issue
3. I changed the PSU with a confirmed working PSU nothing worked
4. Re-applied thermal paste to CPU same issue
5. Switched the CPU with an Athlon II X4 CPU, same issue
6. Re-seated the motherboard, same issue
7. Turned off the PC, unplugged the PSU and removed the CMOS Battery, pushed the power button for more than 10 seconds, but same problem.

I need your guys's help. Not sure what to do. It's not the CPU, because when the CPU was switched I've had the same issue. Any advice would be greatly appreciated

 

[Frick]

So now it does that split second thing all the time? What motherboard is it, and did you upgrade the CPU from something else?

 

[Sasqui]

Not sure if it's much help, but I recently discarded a motherboard that was toasted by a bad PSU. With a new PSU, when I pressed the power button, the CPU fan and video card fan would spin for a moment.. then nothing. Never tried removing the CPU and turning it on. Moved everything to another motherboard and it's all good.

There is a solid state relay on the motherboard that shorts two pins on the PSU connector when the power button is pressed. Those two shorted pins tell the PSU to power on.

Other things to check

CMOS battery good?
CMOS clear jumper set in the correct position?

 

[Slizzo]

I know my ASUS boards spin the fans for a sec after power on then the PC appears to power off, if you let it sit it will boot completely in about 5 seconds. Have you waited to see if it boots?

 

[more123]

So now it does that split second thing all the time? What motherboard is it, and did you upgrade the CPU from something else?

It does it all the time and when left unplugged over night in the morning it turns back on but then again when it goes to sleep for more than 10 minutes it shuts off.

 

[more123]

Not sure if it's much help, but I recently discarded a motherboard that was toasted by a bad PSU. With a new PSU, when I pressed the power button, the CPU fan and video card fan would spin for a moment.. then nothing. Never tried removing the CPU and turning it on. Moved everything to another motherboard and it's all good.

There is a solid state relay on the motherboard that shorts two pins on the PSU connector when the power button is pressed. Those two shorted pins tell the PSU to power on.

Other things to check

CMOS battery good?
CMOS clear jumper set in the correct position?

The thing is the computer turns on ok without CPU. I tried a CMOS battery from a different machine and no luck. I think it's a bad motherboard but not sure why it wouldn't turn on with CPU installed.

 

[more123]

I know my ASUS boards spin the fans for a sec after power on then the PC appears to power off, if you let it sit it will boot completely in about 5 seconds. Have you waited to see if it boots?

Hi,
Oh yeh, I tried many times no luck though. It's an Acer branded MB

 

[xBruce88x]

Kinda sounds like it's going into hibernation mode after about 10min in sleep... and your board may not support it fully for w/e reason. try disabling hibernation mode in windows.

 

[Mussels]

The thing is the computer turns on ok without CPU. I tried a CMOS battery from a different machine and no luck. I think it's a bad motherboard but not sure why it wouldn't turn on with CPU installed.

bad diagnosis tool. without the CPU the fans and such spin on, but most of the in built features arent working. so the system wont turn off again on a bad PSU, missing CPU aux power connector, or bad PSU. it gets stuck before they kick in.



at this point, its either mobo, PSU, or CPU at fault.

 

[95Viper]

Which OS?
Which Acer model?
Have you replaced any components?

You really need to list the specs, if you know them. Go to the User CP at the top of this page and in the user control panel... fill out your specs and click on show specs, so all can see.

Not sure if I missed this, however, if you can get into the bios, try booting to a rescue disk (Windows or other) or some other OS and... this > If it went into hibernation, it could be the file is corrupt... you may need to boot into a rescue disk and delete the hiberfil.sys file.

Try a different stick of ram.
Try a different PSU.
If you can ever get into the bios... make sure any sleep\hybrid options in your bios are set correctly for your OS and check the Acer site to see if there is a bios update to fix any related problems.

Sorry, if, not making a half-a** post, but I got a terrible headache and am not functioning at capacity.

 

[Yo_Wattup]

*95Viper is not responding. Windows can close this program or search online for a solution*

 

[more123]

Which OS?
Which Acer model?
Have you replaced any components?

You really need to list the specs, if you know them. Go to the User CP at the top of this page and in the user control panel... fill out your specs and click on show specs, so all can see.

Not sure if I missed this, however, if you can get into the bios, try booting to a rescue disk (Windows or other) or some other OS and... this > If it went into hibernation, it could be the file is corrupt... you may need to boot into a rescue disk and delete the hiberfil.sys file.

Try a different stick of ram.
Try a different PSU.
If you can ever get into the bios... make sure any sleep\hybrid options in your bios are set correctly for your OS and check the Acer site to see if there is a bios update to fix any related problems.

Sorry, if, not making a half-a** post, but I got a terrible headache and am not functioning at capacity.

Win 7 HP 64. Acer AM3410
How to boot into a rescue disk? Do you mean a Windows installation disk? You know this computer would turn on if left unplugged for a day or so. Thers is no hibernation option in Windows, all I got is sleep, restart and shutdown.

 

[more123]

Kinda sounds like it's going into hibernation mode after about 10min in sleep... and your board may not support it fully for w/e reason. try disabling hibernation mode in windows.

Well I don't have a hibernation option. It's a desktop pc not sure if other desktops have hibernation option.
Also I can't diable the sleep mode because I kinda need the desktop to go to sleep to save on energy and log off.

 

[JrRacinFan]

In WIndows 7
Go to Control Panel>Power Options> Click Change Plan Settings of your currently selected power plan> Change Advanced Power Settings>Click "+" by "Sleep">Click "+" by "Hibernate After" changing the timer to 0 then click apply and ok out of it.

EDIT:

Oh also make sure your wake timers are enabled.

 

[stinger608]

Well I don't have a hibernation option. It's a desktop pc not sure if other desktops have hibernation option.
Also I can't diable the sleep mode because I kinda need the desktop to go to sleep to save on energy and log off.

If you need it to "Sleep" then just shut the system down completely. Many of the "cheap" motherboards in pre-built systems are not very reliable, as well as the sub-par power supplies installed. However, I would try shutting it down when your not using it, and see if the same symptoms occur.

In WIndows 7
Go to Control Panel>Power Options> Click Change Plan Settings of your currently selected power plan> Change Advanced Power Settings>Click "+" by "Sleep">Click "+" by "Hibernate After" changing the timer to 0 then click apply and ok out of it.
http://img.techpowerup.org/120215/Capture040.jpg

EDIT:

Oh also make sure your wake timers are enabled.

LOL, I was just going to post that exact instructions.

 

[user21]

check your bios settings, you might need another bios flash i guess.

and check if the processor heatsink is properly installed. processor is heating up and shuts down automatically to prevent death (assuming that you have actually noted the pro n mobo temps).

 

[r9]

If bios chip is removed the board does that it runs second or two and it powers down. Could be corrupted bios. Try blind flash or hotflash if you can find compatible motherboard.