VOGONS


First post, by appiah4

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So, I took an ATX->AT adapter without a power on button and added a rocker switch between PS-On and Ground, and that works fine for turning it on and off. I have two dumb questions:

1. My understanding is that as long as PS-On is low (ie. connected to ground) the PSU remains on - so in essence this allows any ATX power Supply to work with an AT style power button?
2. What kind of voltage and more importantly current is on the PS-On lane and is the button an electrocution risk like an AT power switch (which is basically directly connected to mains voltage..)

Retronautics: A digital gallery of my retro computers, hardware and projects.

Reply 1 of 7, by Tiido

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Yes, this works with any ATX power supply.

Electrocution is impossible on any of the voltages coming out the ATX connector, PS-ON is an input with minimal current on it (few mA at most, though a pullup resistor to +12 or +5V inside the PSU). Mains voltage is not present there unlike AT power switch where the actual power cable is being switched not merely the output of the PSU.

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Reply 2 of 7, by appiah4

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Tiido wrote on 2021-10-25, 10:12:

Yes, this works with any ATX power supply.

Electrocution is impossible on any of the voltages coming out the ATX connector, PS-ON is an input with minimal current on it (few mA at most, though a pullup resistor to +12 or +5V inside the PSU). Mains voltage is not present there unlike AT power switch where the actual power cable is being switched not merely the output of the PSU.

Great, thanks for comfirmin this Tiido, much appreciated.

Retronautics: A digital gallery of my retro computers, hardware and projects.

Reply 3 of 7, by retardware

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Tiido wrote on 2021-10-25, 10:12:

Electrocution is impossible on any of the voltages coming out the ATX connector

This is not true.
Quite a few people have been killed by voltages lower than 12V.
Most of them probably not intentionally.
Read just one example: https://darwinawards.com/darwin/darwin1999-50.html

Reply 5 of 7, by retardware

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Nah, this is not fearmongering.

Most of the deaths involving SELV I read about in the past actually regarded professionals working with SELV devices and then by some incident their skin got pierced, leading to venticular fibrillation.
For example by grabbing a powered device falling down, and getting some wires perforating into the skin/flesh.

So I believe it is not fearmongering to make people aware of the risk involved with the skin getting pierced and getting electrocuted by very low voltages.
Better to be aware and not do stupid things like dying in a bizarre freak accident.

Reply 6 of 7, by Tiido

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Ok, seems resistance of blood can be as low as 50 Ohm per meter, and with enough contact area, depth and right locations, this could indeed provide a case where death can happen from stopped heart. The more you know 🤣

T-04YBSC, a new YMF71x based sound card & Official VOGONS thread about it
Newly made 4MB 60ns 30pin SIMMs ~
mida sa loed ? nagunii aru ei saa 😜