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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

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Atx psu yellow wire [closed]

I have an old 500 watt psu, the yellow cables on the psu box say 12 volts, but with the voltmeter I am testing, it is 6.80 volts!! Is the psu broken? Is there any solution for it? I also tested all ...
Farshid Vosoogi's user avatar
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1 answer
79 views

How do I get correct a correct pwr_ok signal to use a non-ATX power supply in a PC?

I have an old Power Mac G5 power supply from 2003. It's an excellent quality high-power unit which I'd hate to have to throw out. The problem is that it's 100% proprietary. All voltages are the same ...
matias valdez's user avatar
1 vote
2 answers
298 views

ATX power supply's "Power Good" measurement using oscilloscope

I want to measure the power good time of ATX PSU using an oscilloscope. As far as I know, normal time for power good is between 100ms to 500ms. and it is measured according to the picture below, ...
Ali's user avatar
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Latch circuit to cycle power in an ATX PSU

I'm designing a system powered by an ATX PSU. I'd like it to be able to be switched on and off by a momentary switch but also to be able to be turned off by another input. The latch circuit is powered ...
DusteD's user avatar
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1 answer
389 views

ATX PSU standby section starting problem

I am having a problem in a ATX supply. The problem is when I plug PSU to 230 V AC the PSU won't start thus I opened and tested 5vSB not present on wire and also not on diode (IN5822). Thus started ...
Sourav Bhardwaj's user avatar
0 votes
2 answers
101 views

ATX Computer Power Supply Spark in Non-computer Application [closed]

I would like to ask for your assistance with using a Silverstone DA1650 Gold computer power supply (you can find more about it here: Silverstone DA1650 Gold) for a non-computer application. In this ...
Gabriel's user avatar
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1 answer
274 views

How to find minimum load for 5V rail of the power supply? [closed]

I have 450 ATX 12V V 2.2 power supply. I am going to use this power supply as my power bench supply. But I couldn't find the minimum load that takes on 5V rail. Beacuse its pretty old PSU and no ...
P R 3 A C H 3 R's user avatar
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691 views

Maximum Power Draw Through ATX 24-Pin Connector

I'm currently designing a PCB to adapt a proprietary Dell redundant power supply to have ATX pinouts. It's a redundant PSU from a PowerEdge Tower, and while it has an ATX 24-pin connector to the ...
Anton Yukovitch's user avatar
3 votes
2 answers
339 views

Using a PCIe 6/8-pin connector on a modular PSU to power on a car head unit temporarily

I would like to temporarily wire up a standard 650W ATX to power on a car head unit to check if it is working for about 30 mins. Based the pinout below, do I hook up pins 1 and 4 (or 1 and 5) only?
StrangeCode's user avatar
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56 views

Is it possible to use capacitors or diodes to safely connect two ATX PSUs in parallel for more power? [duplicate]

My school is throwing away some old PCs which are all nearly identical. They happily allowed me to get my hands on a couple of parts including the ATX power supply below. As I see from the spec ...
Παναγιώτης Θ's user avatar
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1 answer
133 views

Is there a safe way to get 12 V power from an ATX power supply when the computer is turned off?

I have some LED stripes to illuminate my workspace. Since I have nothing else at hand, I connected it to the 12V rail of my PSU in my computer. This works very well when the computer is turned on, but ...
stebu92's user avatar
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1 answer
473 views

Speaker amplifier on ATX PSU is noisy when PC's 3.5mm jack is plugged in

I'm running a small class D speaker amplifier directly on my PC's ATX 12v rail (like this), so that it switches on when my PC turns on. This works great when I play music on it from my phone, but when ...
aai aai's user avatar
0 votes
3 answers
204 views

Can an INA3221 current sense module be used to read the current in a ATX 12/5/3.3 V computer power supply accurately?

Can an INA3221 module (Triple-Channel, High-Side Measurement, Shunt and Bus Voltage Monitor with I2C- and SMBUS-Compatible Interface) be used to read the current in a ATX 12/5/3.3 V computer power ...
Magezilla's user avatar
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1 answer
78 views

Converting ATX into lab supply trouble

I have been trying to convert an ATX power supply into a lab power supply and ran into some problems. The first one was that the banana plugs I bought had metal nuts and screws, so I used electrical ...
Sky Dickey's user avatar
3 votes
1 answer
254 views

Will a 10 Ω resistor create 2.5 W of dummy load on 5 V line (using an old ATX PSU)?

I am trying to understand something about dummy load resistors. I have an old ATX PSU. It has a 5 V line; maximum is 34 A, but it says it needs a minimum of 0.5 A. That means it needs a minimum load ...
komrad2236's user avatar
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1 answer
131 views

Maximum capacitance on 12 V ATX PSU

I'm designing a fan controller for a PC. It will be controlling 6 fans. I want to start initially with 100 µF tantalum capacitor for each fan. Can 600 µF capacitance on the 12 V line (4-pin, 5.08 mm ...
urhen's user avatar
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2 answers
1k views

DIY 12V computer UPS

I am considering making a 12V UPS for an ATX computer. I would like to know if my concept is sound, (at least halfway so :) ) It's insane that commercial UPS rectify+step-down mains to charge a 12V/...
1N4001's user avatar
  • 163
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0 answers
183 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 ...
Ben Clarke's user avatar
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0 answers
281 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 ...
bgp's user avatar
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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 ...
landings's user avatar
  • 101
1 vote
1 answer
178 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 ...
Mr P's user avatar
  • 13
1 vote
0 answers
71 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 ...
John U's user avatar
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1 vote
2 answers
999 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 ...
user37741's user avatar
  • 275
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1 answer
64 views

Can I plug a Raspberry 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#...
Soleil's user avatar
  • 173
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1 answer
599 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 ...
flashbang's user avatar
-2 votes
4 answers
3k 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 ...
Mauro F.'s user avatar
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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 ...
user1270949's user avatar
4 votes
4 answers
2k 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 ...
steveh7's user avatar
  • 143
0 votes
1 answer
365 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 ...
Jimmy Falcon's user avatar
0 votes
2 answers
2k views

Playstation 2 - power supply 12 V pins

I have a 110 V Playstation 2 which I've been using for more than 10 years with the help of a 220 V to 110 V step-down adapter. The problem is that the step-down adapter has gone bust and the ones ...
Kokachi's user avatar
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1 answer
316 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 ...
miracle genuis's user avatar
1 vote
2 answers
223 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 ...
Alex Santeri's user avatar
0 votes
0 answers
593 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 ...
Clonkex's user avatar
  • 237
0 votes
3 answers
437 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 ...
miracle genuis's user avatar
0 votes
1 answer
1k 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, ...
apadana's user avatar
  • 1,052
0 votes
3 answers
6k 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 ...
apadana's user avatar
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0 votes
1 answer
439 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 ...
Steve Dutky's user avatar
0 votes
1 answer
755 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 ...
Konner Rasmussen's user avatar
1 vote
4 answers
455 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....
Max's user avatar
  • 557
0 votes
0 answers
39 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 ...
Oleksiy Protas's user avatar
3 votes
2 answers
992 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 ...
Tee Jay's user avatar
  • 41
0 votes
1 answer
1k 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 ...
Blackbird's user avatar
  • 101
8 votes
6 answers
5k 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 ...
Tyler Durden's user avatar
  • 2,206
1 vote
2 answers
1k 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 ...
migajek's user avatar
  • 111
0 votes
1 answer
329 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, ...
gabrielepmattia's user avatar
1 vote
0 answers
67 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 ...
Smoking Diesel GR's user avatar
0 votes
1 answer
311 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 ...
Palin567's user avatar
1 vote
1 answer
534 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 ...
Kevin W.'s user avatar
2 votes
1 answer
394 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. ...
Palin567's user avatar
0 votes
0 answers
308 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 ...
Ananiya J. Kesto's user avatar