VOGONS


First post, by renejr902

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Hi guys! I have to know the power switch pinout of a AT power supply. I know all of them have a black, white, blue and a brown wires. I need to connect it to a atx case. ATX case has 2 pins for the power switch. I dont want to make a mistake and burn everything. I will use the power supply in my uploaded picture.

Thanks for answer or help.

( I have a lot of power switch cables with 2 pins, no one with 4 pins. )

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Reply 1 of 18, by adalbert

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You have a pushbutton in that ATX case? It can not be used for turning on AT power supply. There is dangerous 120/240V on AT power supply wires, and a special isolated switch must be used.

Repair/electronic stuff videos: https://www.youtube.com/c/adalbertfix
ISA Wi-fi + USB in T3200SXC: https://www.youtube.com/watch?v=WX30t3lYezs
GUI programming for Windows 3.11 (the easy way): https://www.youtube.com/watch?v=d6L272OApVg

Reply 2 of 18, by TheMobRules

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Yes, you need a switch that is rated for AC mains voltages, and it has to be a latching button, meaning that it "stays pushed". The little switches in ATX case are not rated for mains voltage and are momentary, so they won't work here.

Besides, the switch must have 4 terminals, and you must wire it so that when you press the button, black is connected to brown and white is connected to blue (as indicated in your PSU label).

Reply 3 of 18, by adalbert

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These switches usually look like this:

61+gHAapu8L._SL1500_.jpg
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Maybe something like this also could be used:

71rALSX30uL._SL1500_.jpg
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Repair/electronic stuff videos: https://www.youtube.com/c/adalbertfix
ISA Wi-fi + USB in T3200SXC: https://www.youtube.com/watch?v=WX30t3lYezs
GUI programming for Windows 3.11 (the easy way): https://www.youtube.com/watch?v=d6L272OApVg

Reply 4 of 18, by renejr902

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Oh ok! Hmm i really didnt know. I use my other at case for test. I didnt know about all of this and for a atx case.

I will check all my power switch in my really old stock box. Maybe i have one or more.

Reply 5 of 18, by renejr902

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adalbert wrote on 2020-10-27, 15:42:
These switches usually look like this: 61+gHAapu8L._SL1500_.jpg […]
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These switches usually look like this:
61+gHAapu8L._SL1500_.jpg

Maybe something like this also could be used:
71rALSX30uL._SL1500_.jpg

TheMobRules wrote on 2020-10-27, 15:19:

Yes, you need a switch that is rated for AC mains voltages, and it has to be a latching button, meaning that it "stays pushed". The little switches in ATX case are not rated for mains voltage and are momentary, so they won't work here.

Besides, the switch must have 4 terminals, and you must wire it so that when you press the button, black is connected to brown and white is connected to blue (as indicated in your PSU label).

And what about the at to atx adapter i just bought from china on ebay ? Do i need a special power switch too ? the adapter only qave 2 wries for power switch ? thanks for answer

See pictures i just bough this one a few days ago. it could take 1-2 months to be in Canada.

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Reply 6 of 18, by adalbert

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If you use ATX power supply and this adapter you can safely use any switch, because there is no high voltage. But that switch cannot be momentary, it must hold its position after pressing. You can use a switch like this, you should be able to buy it in any electronic store for few cents. 4 pin switches would also work, you just use only 2 pins.

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You can also just connect these two wires together, without any switch. Then you would be turning your PC on and off with the power switch on the back of power supply.

Repair/electronic stuff videos: https://www.youtube.com/c/adalbertfix
ISA Wi-fi + USB in T3200SXC: https://www.youtube.com/watch?v=WX30t3lYezs
GUI programming for Windows 3.11 (the easy way): https://www.youtube.com/watch?v=d6L272OApVg

Reply 8 of 18, by renejr902

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i got it working with this. Check the picture.
it has 5 pins. But one is for a led that i didnt use.
Thanks again.

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Reply 10 of 18, by Doornkaat

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OSkar000 wrote on 2020-10-28, 04:55:

Is that swithch rated for 120/240v and 10A? Looks like something from a car to me.

I would not use that switch.

I understand the voltage rating, but why 10A when even the PSU fuse is rated at 5A?

Reply 12 of 18, by stu_e_hughes

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wiretap wrote on 2020-10-28, 11:16:
For AT power supplies: […]
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For AT power supplies:

3DFeSFm.jpg

If i'm connecting to this switch just using two wires from the adapter then i'm just connecting the blue and black diagonally opposite right? I have this switch from an old AT case.

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Reply 13 of 18, by kaputnik

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stu_e_hughes wrote on 2023-05-03, 08:31:
wiretap wrote on 2020-10-28, 11:16:
For AT power supplies: […]
Show full quote

For AT power supplies:

3DFeSFm.jpg

If i'm connecting to this switch just using two wires from the adapter then i'm just connecting the blue and black diagonally opposite right? I have this switch from an old AT case.

We'd need a photo where the terminal numbering is clearly visible, or even better the wiring diagram that might be printed on the side of the switch, to determine that.

If I'm to do a qualified guess, you need to connect two terminals straight opposite in the switch rocking direction. Since you're using the ATX - AT adapter, there's no mains voltage involved, and it's 100% safe to determine the correct connection experimentally. Worst thing that can happen is that the PSU simply won't power on 😀

Reply 14 of 18, by stu_e_hughes

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Thanks. I don't see a wiring diagram on the switch. Only amp/voltage info.

The numbering looks like this from top to bottom.

1/3 2/6 (no connectors)
1/2 2/5 (silver connectors)
1/1 2/4 (gold connectors)

Reply 16 of 18, by mkarcher

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stu_e_hughes wrote on 2023-05-03, 09:49:

Just to add. What i'm trying to achieve is just to complete the circuit/join the wires. Nothing more complicated than that.

So you just want to make the AT power supply operate in an ATX system, and have it powered on all the time? You do not want to install a power switch? In that case you would need to pull the plug to turn off the computer. If that is your goal, it is easy to achive: Two of the four wires from your power supply are directly connected to prongs on the mains plug. The other two wires are connected to the power supply circuit. Connect each of the wires connected to the mains plug to one of the wires not connected to the mains plug, and ensure proper insulation. This is mains power on those wires after all.

Reply 17 of 18, by stu_e_hughes

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Sorry, I didn't write it correctly. I just wanted to clarify that all that's happening with the AT switch is it completes the circuit which provides power to the MB.

I thought that maybe some hidden magic was happening and that there was a special way to connect it up, but it seems it literally just joins the two ends of the cable together.

Reply 18 of 18, by mkarcher

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stu_e_hughes wrote on 2023-05-03, 12:12:

I just wanted to clarify that all that's happening with the AT switch is it completes the circuit which provides power to the MB.

To be more precise: The AT switch completes the circuit that delivers 120V AC or 230 V AC to the power supply, which then in turn converts the power to 5 and 12V DC, and provides that to the main board. An improper connection to the AT power switch is a shock hazard jus like a bare wire put into a power outlet. You can rely on safe-to-touch small voltages only after the power has been converted in the power supply. All AT systems I've yet encountered used properly isolated connections to the power switch, though. It only gets dangerous if mice eat the insulation or you do improper modding on that cable.