Dead MB?

brooksp
brooksp used Ask the Experts™
on
Hi,
I have a PC that doesnt switch on at all. I have checked the Power suply and even tried an alternative one. I have checked the switch and its working fine. The connections are all ok. Pressing the on/off switch does nothing- The fan on the power suply doesnt start, there is no beeps or lights. I have tried stripping out everything except the MB, CPU and Power suply but to no avail.
The MB is a INTEL OEM board, it has the number E139761 on it and seems to be the same as Gateway MB #4000532.
The processor is a Slot 1 Pentium 111.
Can anyone help?
Cheers
Paul
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make sure that you have all the "power on" and "reset" wires plugged into the mother board correctly or it will not even power up. Intel is a stickler about that.


Good luck,

NeckusMaxamus
dbruntonQuid, Me Anxius Sum?  Illegitimi non carborundum.

Commented:
Still sounds like a power supply.  I would expect a brief fan movement at least.  Presumably the alternative power supply was known to be working?  If it was working then, yes, RIP MB.
Try powering up the system without memory on the MB. If that doesn't work, try removing the processor also and powering up.  

I know you mentioned stripping the system -- does that include all power connections to anything but the MB?  Make sure nothing else is trying to get power from the PS.  Also, make sure no ribbon cable to drives are connected.

On a MB with Processor but no RAM, you should get a post error beep code.

On a MB with no processor and no RAM, you should get fans spinning, etc. but nothing else.

If neither of these works, try removing the MB completely and re-installing.  It is possible that the MB is somehow shorting to ground, causing the PS to shut off.

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Commented:
It may be that the switch on the case is bad. They work like a door bell button momentary on. You can test this by unpluging the switch from the motherboard and shorting the 2 posts where it was atached. With a screwdriver or coin for just a second if the switch was bad it should turn on the pc.

Or you can switch the power button with the reset button and use it for the power on.
If the fan INSIDE the powersupply isn't working, I'd say it's the powersupply itself! Try connecting something  simple to the socket... like a lamp... perhaps its the powercord???
Never tried it, but I assume the fan should be running even without a MB connected, as even then heat is produced!
try using another motherboard.  If it doesn't work then, it must not be the motherboard.
cables could be plugged in wrong (ie.. red side of IDE cables not facing power cable connections on hardware)

Stupid question but is the power supply switch off or is the outlet not working or switched on?  Check by plugging in a lamp and see if that works...

Have you changed anything to the computer or has anything happened lately that could have caused this?
How many watts is your PS?  Did you build it yourself, or did it come pre-built?  It might be that the PS isn't stong enough for your MB and all those components.  And check the little black plugs that connect to the MB, there are ones for the Power, reset, etc... If they aren't plugged in the button won't work.
Fuse?

Definitely a power supply problem. Even if it is not connected to the motherboard correctly, the fan will still spin. Correct US/European setting 110V/240V? there is a switch on the back of the PSU to set this,

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Commented:
Seems the reset switch was shorting the board in some way.
Worked when i removed the switch

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