Sign in with
Sign up | Sign in
Your question

Dead motherboard

Last response: in Motherboards
Share
March 9, 2010 6:41:21 AM

Hello,
I have:
945GCM4-LF Motherboard,
P4-2.66GHz CPU,
1Gb Kingston RAM,
Western Digital 80 Gb SATA HDD,
Samsung SATA DVD R/RW
Odyssey 450 PA SMPS,

Some days back my PS went dead, but while trying to service it a loose earthing point touched the PCB accidentally and a resistor on the PS got burnt. The PS was connected to the Motherboard at that time. Then I got a new PS and connected it to the Motherboard but nothing happened.
*I tested all the zeners and found them ok.
*I'm getting 5.0V at the violet terminal of the PS.
*5v is also available at the input of Power Button, but when the button is pressed the voltage drops to 0. Short?
*Cant see any burnt components on the Motherboard.

Help.....please!

More about : dead motherboard

a c 156 V Motherboard
March 9, 2010 12:39:47 PM

5 volts on the violet wire is normal. That's the output of the always on standby power supply inside the PSU.

5 volts on the power switch lead is also normal. Pressing the case power switch shorts that terminal to ground. It's a control lead not an output.

Yellow wires should be 12 volts. Red wires: +5 volts, orange wires: +3.3 volts, blue wire : -12 volts, violet wire: 5 volts always on. The gray wire is really important. It should go from 0 to +5 volts when you turn the PSU on with the case switch. CPU needs this signal to boot.

You can turn on the PSU by completely disconnecting the PSU and using a paperclip or jumper wire to short the green wire to one of the neighboring black wires.

This checks the PSU under no load conditions, so it is not completely reliable. But if it can not pass this, it is dead.

Our standard checklist and troubleshooting thread:
http://www.tomshardware.com/forum/261145-31-read-postin...
m
0
l
March 16, 2010 1:36:03 PM

Thanks jsc for the help, i tried the PSU with another mobo and it is working fine. I tried removing the RAM, HDD etc. from my dead mobo but it is not working. Now i may to buy a new mobo, but am not sure about the old processor. it might be damaged as well. please guide.
m
0
l
!