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Power is not always to Power SW pins.

Tags: Hardware, Windows

The on/off switch on front panel works only sometimes. Try to short-start my PC. There is not always power on Power SW pins. Sometimes there is. Other times there no. Have tested the PSU. It supplies power.

Why there is not always power on the Power SW pins?
Help, please.

Topic

Reply To: Power is not always to Power SW pins.

In reply to Power is not always to Power SW pins.

I can only speculate, but it could be a failing power supply that needs to be replaced. Have you tested the connections with an electrical meter? How old is the computer? Is it still under warranty?

birdmantd

In reply to Reply To: Power is not always to Power SW pins.

Thank you.
The PSU is tested 3 times with a wire to see if the PSU fan turns. I do not have a meter. No, it’s not under warrenty.

Causes I’ve run into.

In reply to Power is not always to Power SW pins.

The question is: Why there is not always power on the Power SW pins?

This has a few sources.
1. The standby +5V on the PSU has failed. Rare but happens. A Volt meter is used to see if +5V standby is up on the motherboard power connection.
2. The motherboard has a failure. Swap boards and re-test.
3. A little bit rare but seen as you work hundreds of PCs is a low or dead CMOS battery. Your new techs won’t know this so take it gentle on them. It’s a cheap part often overlooked by the new tech.

rproffitt

In reply to Causes I’ve run into.

Thank you.
1.What does the standby +5V do? Why does it affect Power SW pins having or not having power? Do not have a meter. I tested the PSU by a piece of wire sticking in connectors 4 (green) and 5(black) to see if PSU fan turns.
2. The motherboard. Do not have anyone to swap.
3. COMS battery. Replaced the old battery with a brand new one a few days ago. Did make any difference.

Some links.

In reply to rproffitt

1. https://en.wikipedia.org/wiki/Power_supply_unit_(computer)#:~:text=While%20an%20ATX%20power%20supply,a%20signal%20from%20the%20motherboard.
2. Often a problem for those that want to fix a PC but don’t have parts. To answer the question in advance, to see if it’s the motherboard, you replace the motherboard.

Reply To: Power is not always to Power SW pins.

In reply to Power is not always to Power SW pins.

Plug the PSU power cable into a wall socket or surge protector, and turn on the computer. Most power supply models have a light on back of the unit that glows when it’s powered on. If it doesn’t light, try a different power cable and a different socket to eliminate those items as the source of the problem.1–

Reply To: Power is not always to Power SW pins.

In reply to Power is not always to Power SW pins.

Power is always to SW pin on a large pin header, while power to a smaller pin header on the smaller pins. For example, the power to the I2C pins generally is on SW1 or SW2.

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