Anyone ever try modifying an atx power supply to power monitors or laptop ect

[Pc6777]

Im curious if there's a way to easily modify and or get an adapter to make a normal atx power supply into something that can power monitors/laptops or be a massive USB hub I know the big motherboard connection has to be in use for the PSU to function so I assume it would hook up to that. I put this thread in general beacause it seems like a fun janky discussion.

[Aereldor]

There are easier and far more convenient ways to commit suicide than opening up a power supply and fiddling around with it.

 

Don't do this.

[Pc6777]

11 minutes ago, Aereldor said:

There are easier and far more convenient ways to commit suicide than opening up a power supply and fiddling around with it.

 

Don't do this.

There's no adapter I can plug into the main motherboard power cable to do this? The only way is going inside the power supply which I wouldn't do beacause it's dangerous.

[Aereldor]

If you want USB ports what's stopping you from using the ones on the back of your motherboard?

 

10 port hub for $30 - https://www.amazon.com/Sabrent-Charging-Individual-Switches-HB-B7C3/dp/B0797NWDCB/

[Pc6777]

1 minute ago, Aereldor said:

If you want USB ports what's stopping you from using the ones on the back of your motherboard?

 

10 port hub for $30 - https://www.amazon.com/Sabrent-Charging-Individual-Switches-HB-B7C3/dp/B0797NWDCB/

I have one if those lol, but I was just curious if you could turn let's say a 500 watt atx power supply into a standalone beast charging station that can power laptops and monitors and whatnot.

[mariushm]

A computer power supply outputs 12v , 5v and 3.3v  - it doesn't care what's connected to the cables, as long as it receives the command to turn on (two wires in the 24 pin connector connected together) it will output power on all the cables.

 

So yeah you could power a monitor or a laptop.

 

A monitor will either have a DC In barrel jack connector or will have a built in power supply that takes 110/220v and produces the voltages the monitor needs inside - typically 30...60v for the LED backlight or around 20v for the CFL inverter (if  older style backlight) , maybe 12..24v for an audio amplifier if the monitor has speakers or headphone output, and usually 5v or 3.3v for the actual processor that takes the signal from video card and puts it on the lcd panel.

 

If you're lucky and the monitor has a 12v DC In  barrel jack connector and a 12v adapter, you could easily buy the barrel jack connector and attach wires from it to your atx power supply and power the monitor. 

If it's a different voltage like 16v or 18v - common voltages for laptop adapters so a monitor manufacturer may choose it because it would mean they can get cheap mass produced already made adapters from a company like Delta or FSP and bundle it with their monitors instead of spending money on making their own power supplies , then you would have to buy a step-up dc-dc converter that would raise the 12v from your atx power supply to that voltage value.

 

If the monitor has a built in power supply, you could analyze that power supply and see what voltages it outputs and use step-up and step-down dc-dc converters and produce the voltages needed using those converters, so you could basically attach a standard barrel jack connector and power your monitor with 12v from your computer power supply.

The problem is, to make the monitors cheaper, some monitors will have the power supply circuit board integrated with the backlight circuit which produces the 30-60v or whatever required to light up the leds, so if you want to fully remove the power supply board to make room inside the monitor, you would have to buy a led driver board separately (they're available on ebay and other places)... just means it's more expensive.

 

As for laptops, yeah, you can power it from a computer power supply.

If it's using a 12v laptop adapter, it's straight forward, you could cut the cable or desolder the cable from the adapter and connect it to your atx power supply. 

If it's another voltage, you would either need to modify the power supply to output that higher voltage (which is not always possible), or you would have to  add a step-up dc-dc converter, to raise the 12v to 16v or 18v or 18.5v or whatever voltage it's using.

Some laptops have a 3 pin jack where the 3rd pin actually has a digital signal sent by a chip in the adapter, which tells the laptop it's a proper charger and that it can deliver some amount of power ... for example a charger can say "i'm a travel charger and I can do 35w only"  or the charger could say "i'm the big boy charger that can do 90w"  - based on this data the laptop could enable or disable a dedicated video card or reduce the cpu frequencies to allow the battery to charge up while laptop runs.

If the laptop has such system, you can still do it, but the proper way would be to open up a genuine laptop adapter and determine the chip that sends that signal and take it off and move it to your own tiny circuit board and then you'd reuse the original cable -  the chip would probably be powered with 3.3v or 5v and you have that on the atx power supply (or you could use a cheap 50 cent linear regulator to produce the voltage needed)

 

Some modern laptops charge through usb ... they negociate and switch to 12v or 20v to keep currents low.

With such laptops, you could get a compatible car charger which takes power from the cigarette lighter and that's 12v ... so you could easily take the circuit board from inside such car charger and connect the 12v and ground wires from the atx power supply and the charger is none the wiser.

 

Alternatively, you open up the charger and try to figure out how it works. Most likely it will have a power supply part which will produce 5v...20v so you could remove the ac-dc convertion bits and connect wires with 20v or what the circuit board expects and the charger won't know it's not powered from AC input.

 

 

 

[mariushm]

38 minutes ago, Pc6777 said:

or be a massive USB hub

Modern computer power supplies output a limited amount of current on 5v and 3.3v, because most power hungry components in your computer are powered from 12v.

 

It's quite common for a modern power supply to have around 100 watts budget for the 5v and 3.3v voltages together, but on each voltage the power supply may only be able to output up to 16-20A.

 

For example, here's the label of a cheap 400w power supply : https://www.newegg.com/evga-400-n1-100-n1-0400-l1-400w/p/N82E16817438038

 

 

As you can see, the power supply claims it can output up to 110 watts on 3.3v and 5v together, but it can only output up to

* 5v x 17A = 85 watts

* 3.3v x 18A = 59.5 watts

 

So let's say you want to make a big usb hub ... if you want all usb connectors to be able to provide 2A of current to a device (phone, whatever), then you only have 17A to play with (though realistically, I wouldn't go higher than 14-15A) so at best it would make sense to have only 8-10 USB connectors.

 

IF you want more usb connectors, one option would be to buy a step-down converter which would convert 12v down to 5v and provide more current.

 

There are ready made power supplies for such applications, here's some examples: https://www.digikey.com/short/zfrdc0

 

 

 

[Pc6777]

10 hours ago, mariushm said:

A computer power supply outputs 12v , 5v and 3.3v  - it doesn't care what's connected to the cables, as long as it receives the command to turn on (two wires in the 24 pin connector connected together) it will output power on all the cables.

 

So yeah you could power a monitor or a laptop.

 

A monitor will either have a DC In barrel jack connector or will have a built in power supply that takes 110/220v and produces the voltages the monitor needs inside - typically 30...60v for the LED backlight or around 20v for the CFL inverter (if  older style backlight) , maybe 12..24v for an audio amplifier if the monitor has speakers or headphone output, and usually 5v or 3.3v for the actual processor that takes the signal from video card and puts it on the lcd panel.

 

If you're lucky and the monitor has a 12v DC In  barrel jack connector and a 12v adapter, you could easily buy the barrel jack connector and attach wires from it to your atx power supply and power the monitor. 

If it's a different voltage like 16v or 18v - common voltages for laptop adapters so a monitor manufacturer may choose it because it would mean they can get cheap mass produced already made adapters from a company like Delta or FSP and bundle it with their monitors instead of spending money on making their own power supplies , then you would have to buy a step-up dc-dc converter that would raise the 12v from your atx power supply to that voltage value.

 

If the monitor has a built in power supply, you could analyze that power supply and see what voltages it outputs and use step-up and step-down dc-dc converters and produce the voltages needed using those converters, so you could basically attach a standard barrel jack connector and power your monitor with 12v from your computer power supply.

The problem is, to make the monitors cheaper, some monitors will have the power supply circuit board integrated with the backlight circuit which produces the 30-60v or whatever required to light up the leds, so if you want to fully remove the power supply board to make room inside the monitor, you would have to buy a led driver board separately (they're available on ebay and other places)... just means it's more expensive.

 

As for laptops, yeah, you can power it from a computer power supply.

If it's using a 12v laptop adapter, it's straight forward, you could cut the cable or desolder the cable from the adapter and connect it to your atx power supply. 

If it's another voltage, you would either need to modify the power supply to output that higher voltage (which is not always possible), or you would have to  add a step-up dc-dc converter, to raise the 12v to 16v or 18v or 18.5v or whatever voltage it's using.

Some laptops have a 3 pin jack where the 3rd pin actually has a digital signal sent by a chip in the adapter, which tells the laptop it's a proper charger and that it can deliver some amount of power ... for example a charger can say "i'm a travel charger and I can do 35w only"  or the charger could say "i'm the big boy charger that can do 90w"  - based on this data the laptop could enable or disable a dedicated video card or reduce the cpu frequencies to allow the battery to charge up while laptop runs.

If the laptop has such system, you can still do it, but the proper way would be to open up a genuine laptop adapter and determine the chip that sends that signal and take it off and move it to your own tiny circuit board and then you'd reuse the original cable -  the chip would probably be powered with 3.3v or 5v and you have that on the atx power supply (or you could use a cheap 50 cent linear regulator to produce the voltage needed)

 

Some modern laptops charge through usb ... they negociate and switch to 12v or 20v to keep currents low.

With such laptops, you could get a compatible car charger which takes power from the cigarette lighter and that's 12v ... so you could easily take the circuit board from inside such car charger and connect the 12v and ground wires from the atx power supply and the charger is none the wiser.

 

Alternatively, you open up the charger and try to figure out how it works. Most likely it will have a power supply part which will produce 5v...20v so you could remove the ac-dc convertion bits and connect wires with 20v or what the circuit board expects and the charger won't know it's not powered from AC input.

 

 

 

it seems its  more trouble than its worth, but that was a very in depth response you must do a lot of tech stuff haha. and how would you even connect the cable to the psu? would you jam it in the 24 pin?

[mariushm]

12 minutes ago, Pc6777 said:

it seems its  more trouble than its worth, but that was a very in depth response you must do a lot of tech stuff haha. and how would you even connect the cable to the psu? would you jam it in the 24 pin?

You can buy connectors and plugs from stores like Digikey, Farnell/Newark, Mouser, etc

For example, common DC barrel jack plugs use 2.5 or 2.1 ID plugs and you have either ready made assemblies or your could buy the plugs and solder wires to the plugs.

You can buy connectors to mount on the psu as well

You can buy the pci-e 6pin / 8 pin connectors, pins and a crimping tool, and could make a pci-e  6pin to barrel jack plug cable.

Or, for example, you could buy some basic molex to sata adapter cables, cut the wires in the middle and solder the wires from a cable with barrel jack to the 12v wires.

 

example of ready made cables with the most common barrel jacks : https://www.digikey.com/short/zff87r

barrel jack connectors you could put on the psu case : https://www.digikey.com/short/zff8t5

 

and so on...