Question Power is not always on Power SW pins

[Diban]

PC : Acer aspire M5700, Windows 7 Pro. 32b.

Intel® Core™2 Quad CPU，DDR2 800 SDRAM 4G，GPU has been removed & use on board
Intel® G45，G45T AM2 V:1.0 motherboard，Hitachi SATA 3.0Hb/s 7200rpm 500GB。

Used only now and then for internet only, and for storing some images.

The power switch turns the PC on only once in a while.

Have tried to short-start the PC, the same situation. There is not always power on Power SW pins.

Tested the PSU. There was power.

Help, please.
Thanks.

 

[siaan312]

It is likely weak contact somewhere along the Power SW runs.
When you say short-start the pc, you mean shorting the pins on the motherboard with a screwdriver?

If it doesn't work well like that, I doubt there's much you could do.
Try reseeding the CMOS, though I am doubtful it would do much.

 

[Ralston18]

How was the PSU tested?

PSU: make, model, wattage, age, condition (original to build, new, refurbished, used?

Are you able to see the case Power SW? Ensure that all connections to the switch are fully and firmly in place.

If possible, unplug the switch and test with a multi-meter. The switch may be failing or has failed in some manner.

You may be able to replace the switch.

 

[Diban]

It is likely weak contact somewhere along the Power SW runs.
When you say short-start the pc, you mean shorting the pins on the motherboard with a screwdriver?

If it doesn't work well like that, I doubt there's much you could do.
Try reseeding the CMOS, though I am doubtful it would do much.

Thank you.
What is to reseed the BIOS, please?

 

[Diban]

How was the PSU tested?

PSU: make, model, wattage, age, condition (original to build, new, refurbished, used?

Are you able to see the case Power SW? Ensure that all connections to the switch are fully and firmly in place.

If possible, unplug the switch and test with a multi-meter. The switch may be failing or has failed in some manner.

You may be able to replace the switch.

Thank you.

"How was the PSU tested?"
By a piece of thin wire connecting wire 4(green) & wire5(black) to see if PSU fan runs. Tested three time in three various days & the fan ran every time.

PSU make is LiteOn, model PS6301-08A, made in 2008 for OEM Acer Aspire M5700, 350W.

Power SW? The switch is embedded in the top bezel on the case. I had it removed from the metal case and turned it inside out and saw every thing was firmly attached.

The problem: There is no power on Power SW pins or the pins are malfunctioning.

 

[siaan312]

Thank you.
What is to reseed the BIOS, please?

Reseeding the CMOS means taking out then putting back in (or replacing) the coin cell battery on the motherboard.