Replacement on/off button for pc.

[Circlotron]

I need to replace the on/off button on the pc. No hope of finding an original replacement so I’m just going to drill a hole and put in something else alongside it. Are the contacts momentary on when you push the button or are they push on, push off?

[Dan123456]

I believe I have seen both types used.

Generally the push on, push off I have seen have been in older (like 90’s or 00’s) machines so am guessing the answer is probably momentarily, but can’t be 100% sure.

Do you know the motherboard/ still have the info on that? I believe the documentation for that should say 

Edit: in my experience pulling old computers apart, if hitting the power button instantly turns the computer off, it is likely a push on / push off. However, if you need to hold for 5 seconds or what not, it is probably momentary. I’m not sure if that is a hard and fast rule, but is just something I have noticed 

[magic]

Since the ATX standard (essentially everything made in this century) it's a momentary button connected to the motherboard. Disconnecting the cable and shorting motherboard pins with a screwdriver turns it on.

Under the fancy plastic button there is probably a standard switch than you could buy and replace.

[wraper]

No hope of finding an original replacement

Do you need to replace button or switch behind it? There is nothing special about the switch. Drilling a hole sounds insane to me. Removing a front panel usually expenses the switch.

[Circlotron]

Okay, sounds like momentary. The motherboard is only a few months old and the switch wires go to a tiny connector on the motherboard, not to the power supply. One problem with the existing switch is the wires that go to the front panel are so short you can only move the panel about 20mm away from the main enclosure so getting to the actual switch is a bit of a drama. Let’s see how we go.

[wraper]

It's not like you cannot remove the front panel with the whole wire.

[Circlotron]

Just for now I've connected the reset button to the on/off connector on the motherboard. Computer was randomly stopping and even starting all by itself sometimes during the night. If the problem stops or continues, this will prove whether the switch is at fault or if the motherboard is acting up.

[wraper]

Just be aware that if these are TACT switches are of the same type, they may be in nearly equal condition. And you should have measured switch resistance in open state. It's not like you don't have a multimeter.

[golden_labels]

Just for now I've connected the reset button to the on/off connector on the motherboard. Computer was randomly stopping and even starting all by itself sometimes during the night. If the problem stops or continues, this will prove whether the switch is at fault or if the motherboard is acting up.

That’s not a symptom of a faulty button. Among the last things I would suspect facing a computer randomly turning off.

The button itself is momentary. It must be, because it’s not really switching anything. Instead it performs a job of three separate buttons, one of which acts as if it was a keyboard key. These are: power on (signaled to the motherboard, which then turns on PSU), power off (acting as a key, conveyed to the operating system), “forced” power off (handled by the firmware, usually unconditionally turns off the PSU).

[wraper]

Just for now I've connected the reset button to the on/off connector on the motherboard. Computer was randomly stopping and even starting all by itself sometimes during the night. If the problem stops or continues, this will prove whether the switch is at fault or if the motherboard is acting up.

That’s not a symptom of a faulty button. Among the last things I would suspect facing a computer randomly turning off.

The button itself is momentary. It must be, because it’s not really switching anything. Instead it performs a job of three separate buttons, one of which acts as if it was a keyboard key. These are: power on (signaled to the motherboard, which then turns on PSU), power off (acting as a key, conveyed to the operating system), “forced” power off (handled by the firmware, usually unconditionally turns off the PSU).

TACT switches do fail by growing silver dendrites on the plastic between the contacts. Once they become somewhat conductive devices tend to do weird things.

[magic]

As for turning on in the night, Windows update would be the usual suspect.

Turning off is something computers just do for any reason or no reason at all, nothing unusual
Does it actually turn off, fans stop spinning and so on, or only locks up? Even if the former, it could still be caused by overheating, for example.

[Haenk]

Just for now I've connected the reset button to the on/off connector on the motherboard. Computer was randomly stopping and even starting all by itself sometimes during the night. If the problem stops or continues, this will prove whether the switch is at fault or if the motherboard is acting up.

Power off requires you to press the on/off-button for a couple of seconds - unlikely this is a button issue.
You might want to check BIOS settings for the event "power loss" - usually there is "on/off/same state".

I suspect a PSU issue however.

[BeBuLamar]

You can easily test the button to verify if it's good or bad. Sound like not a button issue.

[Circlotron]

It’s been behaving itself for three days and night so far. That puts the button in the lead at this point. Time will tell.

[golden_labels]

What operating system is it? In Linux you would see clean shutdowns in logs, if that was the button. In some setups (e.g. systemd) it would even indicate where the shutdown signal came from.

[RayRay]

It’s been behaving itself for three days and night so far. That puts the button in the lead at this point. Time will tell.

You could get a new button from aliexpress:
https://www.aliexpress.com/item/1005005034925438.html
I'd recommend the 19MM size (or 16 if you don't have enough clearance).
You'd need to drill a center hole, and then use a step drill to expand it further. You couild use either one of the drive bays, or place it on the top. Once the hole is in place, it's fairly straightforward, and you just manually tighten the nut from the inside

[wraper]

This thread makes me cringe. OP who cannot be bothered to measure the switch despite apparently being proficient in electronics. Then that fixation on mauling the PC case instead of just replacing it with cheap original type. Hint: only the most common types of switches are used in PC enclosures.

[Circlotron]

This thread makes me cringe. OP who cannot be bothered to measure the switch despite apparently being proficient in electronics. Then that fixation on mauling the PC case instead of just replacing it with cheap original type. Hint: only the most common types of switches are used in PC enclosures.

The original switch has a clear plastic ring around it that a blue power LED shines through. And it has this weird mounting bracket. It's not a simple push button that you would find anywhere.

[Circlotron]

What operating system is it? In Linux you would see clean shutdowns in logs, if that was the button. In some setups (e.g. systemd) it would even indicate where the shutdown signal came from.

It's the missus' Win10 setup. Not my Linux box.

[wraper]

This thread makes me cringe. OP who cannot be bothered to measure the switch despite apparently being proficient in electronics. Then that fixation on mauling the PC case instead of just replacing it with cheap original type. Hint: only the most common types of switches are used in PC enclosures.

The original switch has a clear plastic ring around it that a blue power LED shines through. And it has this weird mounting bracket. It's not a simple push button that you would find anywhere.

Post a photo. That plastic ring probably is not even part of the switch. But there are plenty of off the shelf switches with lighting capability too.