# New self-built computer not working

## Thms.

Hello,

I recently bought new hardware and built the computer yesterday.

It's not the first time I'm building a PC but the PC just doesnt boot, with the power button neither with a screwdriver.

I tried to remove all the RAM, graphic card it still doesnt put.

I test if the Seasonic PSU is working by using a metallic "thing" and contact the black & green: the PSU fan is then working.

When I plug it back on the motherboard it still doesnt work.

All the hardware is brand new, how can I be sure that the motherboard is the source of my problems ?

Thanks,

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## Zhaozhou

Many motherboards have an LED that emit light as soon as they get power.

Also, if your videocard or memory is failing, your motherboard should beep (loudly).

But to be completly sure you could switch to a working motherboard, if you have one.

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## NeddySeagoon

Thms.

Silly question time.  Most motherboards are shipped with the 'Clear CMOS' jumper in the clear position.

This also holds the CPU reset, which prevents any CPU activity at all. This is done so that the battery does not power the BIOS clcok while the motherboard is in storage.

You did check the jumper ?

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## Thms.

 *NeddySeagoon wrote:*   

> Thms.
> 
> Silly question time.  Most motherboards are shipped with the 'Clear CMOS' jumper in the clear position.
> 
> This also holds the CPU reset, which prevents any CPU activity at all. This is done so that the battery does not power the BIOS clcok while the motherboard is in storage.
> ...

 

Gonna check this later.

I don't have a LED for the power activity.

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## Thms.

No, no jumper on my CMOS pins :/

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## NeddySeagoon

Thms.

To get any further, you will need a voltmeter. If you don't have one, the next step to to swap PSUs.

If you have a voltmeter - measure the Pwr_Good voltage after you have switched the system on.

If that stays bad, the CPU is held reset and nothing happens, just like with the CMOS jumper.

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## eccerr0r

If you short green+black and the PSU fan turns on, and if you plug into the MB and press the power on button but PSU fan does not turn on, then likely it is a motherboard issue.  The CMOS jumper was a very good idea to check, as lots of boards disable power on when CMOS is turned off (for clearing).

A lot of things need to work for the PSU to turn on its fan - the standby power of the PSU needs to be working to even allow shorting GND and the green power on signal to work -- so likely the PSU is fine.  A voltmeter to check the standby power should still be done in case that's not being ported out of the supply properly.

If the fan is turning on with the motherboard, then it's time to check Power Good.  But from the description so far, we haven't gotten to that stage yet.

(Does this thread belong in OTW?)

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## Thms.

Yes, the PSU works when I short green+black.

I tried to do a clear CMOS yesterday, doesn't work (as the PSU fan doesnt turn I doubt it will).

I would like to precise again that NOTHING works, not ANY fan or ANY noise.

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## eccerr0r

one last thing to make sure is to make sure the back of the m/b isn't shorting against some metal, and also make sure you got the right pins for the power switch..  Otherwise it's likely the motherboard that was DOA.  Checking the +5 Standby (purple) would be the final check.

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## NeddySeagoon

Thms.

If you get no fans, the +12v from the PSU is not on.  Clear CMOS only works when the PSU is off, so I doubt you needed it but it will have been harmless.

If you short green+black when the PSU is connected to the motherboard, do the fans start?

Does the PSU scream (literally) ?

The scream is the PSU going into an overcurrent condition, then resetting, 1000s of times a second.

It indicates a short circuit on one or more of the outputs.

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## Thms.

Problem solved   :Laughing: 

Was just a really dumb error, misread the F_PANEL schema.. and spend 2 days on this.

Sorry guys!

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## eccerr0r

ha... yeah definitely valuable to check the power switch pins again.  I had a m/b that labeled the power switch pins ambiguously and I hooked it up wrong... and thus wouldn't power up.

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