PC tower will not switch on. I have change thc psu for the same one in the unit but still no power can u help thanks

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Originally Posted by laurendebbie

pc tower will not switch on. i have change thc psu for the same one in the unit but still no power can u help thanks

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Things to investigate:

1. Electrical supply - Wall outlet? Surge suppressor? Master switch on power supply?
2. Power button/switch in case - Faulty? Connected to motherboard header correctly?
3. Motherboard - Faulty?

Does tower "grunt" or show any signs of life when power button is pressed?

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Originally Posted by Scleros

Things to investigate:

1. Electrical supply - Wall outlet? Surge suppressor? Master switch on power supply?
2. Power button/switch in case - Faulty? Connected to motherboard header correctly?
3. Motherboard - Faulty?

Does tower "grunt" or show any signs of life when power button is pressed?

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Tower showes no sign of life when you switch on PC power button

Have you tried another outlet or maybe plug something else into the outlet and see if it works

Check wall switches, if using power strip, connect directly into wall

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Originally Posted by laurendebbie

tower showes no sign of life when you switch on pc power button

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How about with the case cover removed - fans spin for a second, etc?

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Originally Posted by Scleros

How about with the case cover removed - fans spin for a second, etc?

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Hi scleros yes the spins for about a second then powers down thanks

Check motherboard battery.
Check connection of all wires from psu.
Check fuses (if any in psu aor motherboard).
Did you connect wires from case to motherboard correctly (power switch) ?

If it won't help - motherboard might be dead

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Originally Posted by laurendebbie

hi scleros yes the spins for about a second then powers down thanks

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The usual reasons for this behavior with ATX type power supplies are:

• Once turned on by motherboard via power switch, power supply does not assert PWR_OK typically due to faulty supply. Since power supply is new this probably isn't the case.
  
  
• Motherboard not properly grounding PS_ON# to turn power supply on, and then keep it on, or is detecting a problem and switching PS_ON# back high. So, either a faulty motherboard or a problem component. At this point I usually disconnect everything from the board except for processor and minimum RAM and try to determine if it is board or another component. But, before doing that, try reseating (remove and reinstall) the memory modules and discrete video adapter card, if any.

More Info:
ATX 2.2 Specification, Section 4.1.x

Yeah resort to your MB manual and check switch settings.
Also what type of CPU/MB. Usually not having that extra 4pin pSU connected will do that check form factor

I would look at the thermal paste between CPU and CPU fan. It may have become dry. You mentioned that the fan spins for a few seconds then stops. Motherboards have failsafe mechanisms that stop a CPU from melting a motherboard when their average temperature spikes too quickly. The board switches itself off. Head to your local computer repairs company and they're bound to have some thermal paste for you.