PC power supply problem

Hi,

My PC went dead (no display, but the CPU fan spins). Looking at this, I naturally suspected the motherboard, but then I found the system works fine with another poer supply.

Funny thing is, the defective(?) power supply seems to give all the voltages all right, but just doesnt start up the system.

Could this be a 'power good' signal issue? If it is can it be tested?

Another pointer: earlier, the CPU fan would initialise only after pressing the soft-on power supply switch on the mobo. Now, it starts the moment the system is powered up. On the other hand, if no load is connected to the PS, it seemingly behaves exactly as it should; off till soft switch pressed (green wire connected to ground).

Before buying another supply, I'm wondering if there is anybody has seen this specific problem, and managed to fix it?

Thanks and Regards,

Anand

ved snipped-for-privacy@hotmail.com ha escrito:

I don=B4t understand your question. You already found that your computer works OK with a different PSU, just replace it and be happy.

Without a 3.5 digit multimeter, then you don't know if voltages are OK. Important are voltages on any one of each purple, red, orange, and yellow wires that should exceed 3.23, 4.87, and 11.7 volts. What are (and post) your voltages?

Handshaking involves green and gray wires. Voltage on green wire should exceed 2.0 volts before switch is pressed and drop to less than

0.8 when switch is pressed. Gray (power good) should exceed 2.4 volts within seconds after a switch press.

If Power Good does not remain stable, then meter should identify which red, orange, or yellow wire voltage is going defective first.

N> ...

Just replace the PSU and quit worrying about it. PSU die and go bad regularly. Be thankful it didn't go bang and take out the mainboard along with other stuff !

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Baron: