Questions tagged [atx]

ATX is the standard for PC power supplies. It has +3.3 V, +5 V, and +12 V. They share a common ground. It has a PS_ON# signal which needs to be grounded to turn it on. Don't open power supplies that run on line voltage (AC). They have dangerous voltages and currents inside

Filter by
Sorted by
Tagged with
1 vote
0 answers
50 views

Detect if PC power is on/off then turn a TV on/off using an Arduino

I'm building an arcade cabinet using an old PC and an old(ish) Bush LCD TV as the monitor. The TV is connected to the PC graphics card via HDMI and all is good. However, the problem is that I want the ...
user avatar
0 votes
0 answers
51 views

ATX PSU load sharing and failover design

I'm trying to arrive at a solution for lower cost ATX power supply which will supply about 250W, has two separate inputs each capable of supplying the full load in case of failure/disconnection but ...
user avatar
  • 273
-1 votes
1 answer
72 views

Is it safe to keep PS_ON grounded?

I want to disable the 'soft power off' feature of an ATX power supply. So I think of connecting PS_ON and GND with a tweezer and keep it. But when the motherboard wants to shut down and sends high ...
user avatar
  • 101
1 vote
1 answer
48 views

Switching ATX PSU with a NPN transistor controlled by a 12V signal

I searched everywhere but I can't find a circuit to turn on a PSU with a 12V signal. I know that PS_ON has an internal pullup but its value may change by vendor. So I don't know if I can use this ...
user avatar
  • 13
1 vote
0 answers
66 views

Detect power/run status of PC in hardware

This may well be a daft question and/or a failure to google effectively (and apologies if this would be a better fit on SuperUser or somewhere else?) but is it possible, in low-level hardware, to ...
user avatar
  • 6,629
1 vote
2 answers
411 views

Connecting PSUs in parallel

It's certainly have been asked here but answers seems mixed. So for my project I need to power an ATX motherboard with extra 3.3V rail (there's a separate connector on MB for this). I will be using ...
user avatar
  • 253
0 votes
1 answer
39 views

Can I plug a pi pico (5 Vdc) to an ATX 2.4?

I have a Corsair SF450 (ATX 2.4) not connected to any PC motherboard; however, I believe it's providing a 5 VDC supply to the mini-USB, by the ATX pin 6 or 4 for (+) (https://en.wikipedia.org/wiki/ATX#...
user avatar
  • 159
0 votes
1 answer
137 views

ATX power supply - switching PS_ON

I need to control two computer power supplies so they turn on and off at the same time. Since the primary power supply doesn't use a standard ATX motherboard connector, I can't just splice the PS_ON ...
user avatar
-2 votes
4 answers
370 views

Where can I get +5VSB from a motherboard?

I have a computer I'm using as a server, I would want it to turn on on its own when power is cut off, and I figured the easiest way is to connect a micro, maybe an attiny85, that will short the power ...
user avatar
0 votes
0 answers
29 views

Power switch for 8Pin ATX Connectors

What would be the best way to make a power switch for the 8-pin ATX Power Connectors? Can I just join all the yellow (12V) wires together and then use a high current switch to toggle them ON/OFF? Also ...
user avatar
3 votes
4 answers
1k views

Driving 5V logic output to 3V3 logic input and an LED simultaneously

Background: I'm attempting to control an ATX power supply. I want to read its 5V power good signal and send it to a 3V3 Raspberry Pi Pico GPIO input, and simultaneously power an indicator LED. I think ...
user avatar
  • 133
0 votes
1 answer
134 views

Step-down converter in an ATX PSU, why?

I was recently looking at a 500W PSU schematic, and found out they used step-down converters on 12v and 5v output. Schematic is attached(pls see hi-res at https://ibb.co/nbDRJPq) The D2 diode charges ...
user avatar
0 votes
2 answers
450 views

Playstation 2 - Power Supply 12V pins

I have a 110V Playstation 2 which I've been using for more than 10 years with the help of a 220v to 110v step down adapter. But the problem is that the step down adapter has gone bust and the ones ...
user avatar
  • 624
0 votes
1 answer
242 views

What is the purpose of this circuit from an ATX power supply?

I am trying to understand the working of this circuit but I didn't get the exact intuition. The circuit is extracted from an ATX power supply. The objective is to have 5V and 3V3 (and of course others ...
user avatar
1 vote
2 answers
129 views

Can I run an ATX power supply close to full load, for a long time? [closed]

Ive been told that it is good to follow "80% rule" when using ATX power supplies, but for server supplies I can nearly max out no problem. Ive been wanting to use a Corsair 1200W power ...
user avatar
0 votes
0 answers
162 views

LM317 digitally-controlled constant current power supply

I'm designing and simulating (with the intention of building) a lab power supply. I like a challenge so I'm trying to make it digitally controlled (also because I'm a programmer). I'm doing this for ...
user avatar
  • 125
0 votes
3 answers
248 views

Is it normal to have 0 volts between the AC inputs of diode bridge rectifier?

I have some basic knowledge about electronics. I am trying to repair an ATX 250W power supply. In the picture below, I measured 0V with my DMM between points C and D (AC inputs of diode bridge ...
user avatar
0 votes
1 answer
361 views

Damages caused by inversely connected PCI-e power cable?

Recently, I used a 6-pin to 8-pin PCI-e convertor to power a graphics card (see the picture). After installation, each time I turned on the switch on the PSU and pressed the power button on the PC, ...
user avatar
  • 715
0 votes
3 answers
2k views

What is the maximum power for an 8-pin PC PSU cable?

I have a non-modular 600W PC PSU which has one 8-wire (3 yellow, 5 black) cable split and connected to two 6+2 connectors (see the image below). I've read that according to the ATX standard, an 8 pin ...
user avatar
  • 715
0 votes
1 answer
176 views

How to determine preload resistance needed for an ATX power supply to power up?

I want to make a benchtop power supply from a 20 pin ATX power supply from the last millennium. I have seen posts, but still need help. So far, I have shorted PWR_ON to ground and have connected an ...
user avatar
0 votes
1 answer
266 views

15v from 20pin and/or 24pin ATX Power Supply. Connecting PSU circuits in series

I have a portable 12v car battery charger, jumper, maintainer, and inverter with integrated USB ports, 12v car adapter slot, jumper clamps, emergency LED light, and a 3 prong 110v/60hz wall outlet. It ...
user avatar
0 votes
4 answers
195 views

Using ATX power supply in industrial electronic projects

I have two main questions: 1. Can you use ATX power supplies in industrial projects? I see lots of DIY projects where they convert an old ATX PSU into a lab bench power supply or powering DIY projects....
user avatar
  • 447
0 votes
0 answers
37 views

Grouping 12V ATX lines for measurements

I'd like to measure the power draw of my CPU. The way that seems the most straightforward to me is to cut into the ATX12V cable and put a shunt based sensor in the middle of the 12V line. Now in the 4 ...
user avatar
0 votes
2 answers
276 views

ATX PSU and offline UPS compatibility

Specifically how well can an ATX PSU and in turn the Computer it is powering cope with power loss for x miliseconds during the changeover from Grid AC to offline UPS inverter AC Can I use offline UPS ...
user avatar
  • 11
0 votes
1 answer
581 views

Powering many external 3.5" HDDs (USB) by an ATX PSU

I have many external USB disks like this one, that I would like to power from a single dedicated ATX PSU, instead of one 12V power adapter per disk. Because each power adapter would take one power ...
user avatar
  • 101
8 votes
6 answers
4k views

Why are DC-DC ATX converters so big?

I watched an interesting video in which the caster reverse engineers a modern 850W computer PSU. From this teardown one can see that 90% of the bulk of the PSU is devoted to synchronous conversion of ...
user avatar
  • 2,128
1 vote
1 answer
310 views

ATX PSU turns off under heavy 12V load, unless increased gradually

Following the well known instructions I've built the PSU from a spare 500W ATX. I've used 10 Ohm resistor for artificial load on 5V line. When I connect 1A load to 12V line, the ATX shuts off. I need ...
user avatar
  • 111
0 votes
1 answer
142 views

Use a PC PSU for powering a Raspberry Pi cluster and number of 5V+ cables

I need to power a cluster of 8 Raspberry Pis 4 and I have a 480W PC PSU with a maximum load of 28A on 5V+. My question is really simple and dumb (sorry for that) but I did not found a precise answer, ...
user avatar
1 vote
0 answers
65 views

Computer power supply outputs 5.20 volts at 3.3 volts rail

I got an old 420 watt Tagan power supply. It seems pretty good quality. I wanted to convert it into a bench power supply. It worked fine until I THINK I messed things up. I’m not sure if i actually ...
user avatar
0 votes
1 answer
113 views

Figuring out ATX Power Supply max output

I have a Delta DPS-400AB-17B power supply, and I am planning to change over some of the connectors to different ones. I want to make sure I don't overload any of the 12v 18awg wires, so I am figuring ...
user avatar
1 vote
1 answer
270 views

ATX Power Supply Pin Material? (gold or tin)

I'm planning to use an ATX power supply to power a small set of 12v devices. I've read plenty of guides about adapting ATX -> bench supply, but I can't seem to find any mention of the connector ...
user avatar
2 votes
1 answer
214 views

Is it bad to load one rail of a power supply vastly more than the other?

I am trying to modify a Delta DPS-400AB-17 server 1U power supply to support a desktop motherboard and graphics card. The power supply has an 8 pin 12V EPS connector attached to a 21A 12V (252W) rail. ...
user avatar
0 votes
0 answers
222 views

How to calculate the average current

I have an ATX which the yellow wire is "+ 12 v ,18 amp" and "blue is -12v , 1 amp". When I use them together I got 24 v but I am confused how to calculate the max ampere. How to ...
user avatar
0 votes
0 answers
137 views

ATX power supply turns off when used with DIY boost converter

I am trying to build my own step-up boost converter. I have my connections as shown in the following schematic (except for the one circled in red.) First I powered up my step-up module with a ...
user avatar
  • 115
-1 votes
1 answer
310 views

can atx power supply the intel nuc and egpu [closed]

So I want to power my Nuc (mini-pc) with ATX psu and the reason is I built my own egpu(external graphic card) and i would like to throw the nuc in there powered by the same psu that runs the egpu ...
user avatar
  • 1
2 votes
0 answers
108 views

ATX power supply doesn't cut the current after being turned off

I made a power supply for my electronic projects using a ATX power supply of a older computer and used a button connecting the black and green wires to turn it on/off. I noticed that sometimes when I ...
user avatar
1 vote
1 answer
128 views

ATX PSU turns itself off when uploading sketch to Arduino

I'm trying to power a stepper motor with the 5V rail of an ATX PSU and control it using arduino. To keep the PSU running, I have shorted the PS_ON pin to ground. ...
user avatar
1 vote
1 answer
159 views

Building my own on-off button for a PC

I'm looking to build my own power button for my computer. Most motherboards have a pair of PWR_SW pins that your case power button typically attaches to via two ...
user avatar
  • 111
0 votes
1 answer
105 views

What could be the reason an ATX PSU triggers OVP?

I have a broken MARS MP600 PSU that I am trying to repair. Everything looks good but when I turn it on (grounding PS_ON) the outputs do not maintain the voltage. The output signals go to the rated ...
user avatar
  • 157
0 votes
1 answer
300 views

ATX power supply doesn't turn off after PS_ON wire is disconnected from GND

I'm using an old ATX power supply to power a PlayStation 3. I've built a small circuit to make the power supply only fully turn on when the PS3 is turned on, by using an optocoupler that connects the ...
user avatar
  • 11
0 votes
1 answer
53 views

Can I use 1 yellow 12V wire to power 2 12V pins?

I'm trying to mod a C8220 Dell (mini 18-pin power) from an old ATX supply. I want to know if it's okay to use 1 yellow wire to supply 2 yellow sockets on the 18-pin. Thank you.
user avatar
  • 101
1 vote
1 answer
158 views

Converting negative voltage to positive

I am adding an ATX power supply as a bench power supply to power accessories on my model railroad layout. I prefer to run some lighting accessories at +7v, but obviously a power supply has +3.3v, +5v, ...
user avatar
0 votes
1 answer
93 views

Swapping power supply - need clarification on grounding (AG & DG)

The internal power supply on my Yamaha keyboard was broken while moving house (PCB is nearly snapped in half) and because it's 30+ years old it's not easy finding a NOS part replacement. I've found ...
user avatar
0 votes
2 answers
2k views

How to make +12v standby power from ATX power supply?

Can I make a 12v SB line from the existing lines on this ATX power supply? I'm told that +/- 10% voltage is acceptable. Can I combine a (red + orange + purple) 5V + 3.3V + 5VSB = 13.3VSB? I'm working ...
user avatar
  • 101
0 votes
1 answer
135 views

How safe is to work on an ATX PSU as a bench power supply?

I'm trying to convert an old ATX PSU into a workbench supply. I saw there are many safety warnings about discharging the internal capacitors before opening the PSU. I'm not really concerned with it as ...
user avatar
  • 3
0 votes
1 answer
81 views

ATX Power supply and its protective features - not happy with motor as load?

I'm building a chicken coop opener - I've build my circuit (let's say arduino) with a DS3231 clock module and if functions as follows: My DS3231 will pull down its interrupt pin which is connected to ...
user avatar
1 vote
1 answer
930 views

Creating a DC input ATX power supply using buck converter

I am working on a project which requires me to use a battery to run a computer. I planned to work with a 24V battery connected to a DC input (24V,1000W) ATX power supply and connect it to the PC. But ...
user avatar
  • 11
0 votes
0 answers
120 views

Windshield motor with ATX power supply keeps shutting down

I need to connect my windshield motor (12V) to my ATX power supply from old computer. I've tested the motor on my bench power supply and i draws around 1,5A @ 12V, so it should be well in range of the ...
user avatar
0 votes
1 answer
224 views

If I use a 19V 4.7A supply to a MAX 250W ATX power supply am I an idiot or should it be safe enough?

I can do the maths, I get near 90W, but I'm only planning to draw under a quarter of the power supplies (ebay link) rated max of 5V/12V combo (estimated load 30W). I therefore consider my 19V old ...
user avatar
  • 111
1 vote
0 answers
432 views

EPS12V 8pin from ATX PSU with two separate 12V rails

This is your standard EPS/ATX12V connector used for feeding the main processor VRM on a computer motherboard. The two 4pin connectors can be attached together to create an 8pin connector. The top four ...
user avatar
  • 103