Before we begin, here is some background information on computer power supplies. At uses the p8 and p9 as the main connectors where it. It had quite a lot of faulty components, so instead of fixing it, i decided to reverse engineer some schematics, explain how does it. Hs drive carr, 1 inch, black 17, appropriate screwswashers. Some power supplies have a manual switch for selecting input voltage, while others automatically adapt to the mains voltage most modern desktop personal computer power supplies. Schematic of modification of the single mosfet forward converter atx pcsupply into an adjustable stabilised power supply of 315v optocoupler, which turns on the supply from a standby mode. Two types of power supply at and atx power supply atx has a special power soft switch that can enable the pc to go into suspend or sleep mode. Converting an atx power supply into a dc bench supply this article is the first in the projects category. Oct 28, 2016 the basic operation of a switchmode power supply is fairly straightforward, and atx supplies have very few deviations from the norm. Schematic of modification of the single mosfet forward converter atx pc supply into an adjustable stabilised power supply of 315v optocoupler, which turns on the supply from a standby mode.
Atx300p4pfc pc power supply sch service manual download. Application manual for power supply noise suppression and. Jan 15, 2010 the power supply schematic that was posted actually originates from here. How to modify an at atx computer power supply to a 315v.
Converting an atx power supply into a dc bench supply. The basics t he power supply is a large metal box, mounted inside the pc that provides power to the motherboard and various peripherals. Power supply design guide for desktop platform form. Step 1 affix the power supply to the case tightly with 4 screws included. Atx power supply 450 watt circuit diagram datasheet. Watts amount of power typical pc today use about 500 watts ohms resistance. There is a brief explanation with that particular schematic explaining the theory of operation. My next idea was, to modify an atxcomputerpowersupply from 12v to 18v and connect a unmodified original atxpowersupply with a modified 18v to reach 30v and 10a.
Some dell supplies are wired like the dell diagram, others are standard atx, so its worth a quick check. My roommate adam told me about somebody online who had converted a spare atx computer power supply into a lab bench power supply, so i decided to try and do the same thing. The diagram below shows a partial schematic of a 450 watt atx power supply. An annotated schematic of 250w atx power supply with active power factor correction \pfc\. Some will shut down after few seconds fan rotate for a while and stop you can either use dummy loads like used motherboard, hard disk and even atx power supplies tester to test out the power supply. My next idea was, to modify an atx computer power supply from 12v to 18v and connect a unmodified original atx power supply with a modified 18v to reach 30v and 10a. This simple test allows you to quickly determine if the source of a power problem is. Scope this document outlines a reference atx power supply that complies with the atx specification, version 2. If youre using this pinout table to test power supply voltages, be aware that the voltages must be within atx specified tolerances. They are the most commonly used power supplies for computers. Aug 09, 2019 how to add variable voltage to your atx based bench power supply. Use a pc power supply as a bench supply with the atx ps adapter. Hello, ive just finished the conversion of my old atx power supply for icharger 208b. Atx supplies also have a stanby power supply, usually 5v at about 1a or so.
The integrated circuit tl494 utilised in this design is a very common power circuit pc power supplies having about 200w output. There is a mains rectifier and filter, a pair of highvoltage. Atx power supply repair posted on may 26, 2011 probably the most common failure that can occur in a computer is the power supply failure, and this is understandable. With the introduction of this third generation, highefficiency atx power supply, on semiconductor has shown that with judicious choice of design tradeoffs, optimum performance is achieved at minimum cost. I would make sure both supplies were grounded well to the chassis, i.
The power supply schematic that was posted actually originates from here. Pc power supply tester computer power supplies atx. Not quite 101 uses for an atx power supply hackaday. It was the first major change in desktop computer enclosure, motherboard and power supply design in many years, improving standardization and interchangeability of parts.
Atx power supply 18v and 30v modification simon wyss. The power on signal is a pin on the main 20pin output connector, which needs to be connected to ground for the power supplys main converter to start up. May 26, 2011 atx power supply repair posted on may 26, 2011 probably the most common failure that can occur in a computer is the power supply failure, and this is understandable. A step by step guide about 200 watt atx pc power supply function. When i opened up the power supply, i found the following wires inside. This image shows testing a power supply with an atx power supply tester. To start up at power supply, turn on the switch located in ac input side. Now, the power supply schematic looks a bit like this. Updated typical power distribution tables for all power supply form factors and updated minimum loads. View and download ultra products 400 watt atx power supply quick manual online. It is intended to provide additional power supply design information not detailed in.
Atx power supply service manual free download,schematics. Turn a computer power supply into bench power make. It includes supplementary information not expressly detailed in the atx. However, of late, it does not always mean that ac input is directly turned on or off. Highefficiency 255 w atx power supply reference design. Since this power supply tester is able to detect the 5v circuit, you will not mistakenly test old power supplies as bad. What is the difference between atx and at power supply. This instructable will show you how to make a very good bench power supply using mainly recycled parts. Sep, 2005 the cost of a generic atx case and power supply is fairly low and its not unheard of to end up with a spare after a computer fails. Today i tried to repair a big 850w atx computer power supply.
The required output voltages are determined by the number of turns on each secondary. How to combine 2 psu, so cheaper and more powerfull hard. The basic operation of a switchmode power supply is fairly straightforward, and atx supplies have very few deviations from the norm. This design for an external adapter lets you use the power supply without modifying it. The computer power supply is not designed for 17v operation, that high operating output voltage, it will most likely need rewinding of the transformer. How to add variable voltage to your atx based bench power. An evaluation board which works in any standard atx case and uses a standard atx power supply is cheaper to use than one which requires a. Bestec power supplies can be found in hundreds of top name computer brands. This is the really the mark ii, you can see mark i here. I scrapped the power supply from the pjrc mp3 player, and started the conversion. Short the emitter and collector together they are on the primary side. If its a bestec power supply youre looking for then chances are we have it.
Make a bench power supply mostly from recycled parts. Modern personal computers universally use switchedmode power supplies. Difference between atx power supply and at power supply. Use a pc power supply as a bench supply with the atx ps. It would be helpful to have an assortment of heat shrink tubing and a heat gun, plus a hot glue gun, a soldering gun, electrical tape, some solder and. Apr 23, 2014 this design for an external adapter lets you use the power supply without modifying it. At uses the p8 and p9 as the main connectors where it connects to the. Similar circuit is used in the most power supplies with output power about 200w. Pc power supply tester computer power supplies atx power.
Below is the complete pinout table for the standard atx 24 pin 12v power supply connector as of version 2. Scope this document provides design suggestions and reference specifications for a family of power supplies that comply with the atx specification, version 2. Specifications the design closely follows the atx12v version 2. This power supply was designed for atx and provides a power output of 200 watt. Most computer psus range from about 150w up to 500w so there is plenty of power.
Here you have the schematic diagram of atx pc power supply from dtk company. When i finished my first bench power supply i was really happy, and used it. Converted atx power supply voltage combinations pcb smoke. Dec 10, 2012 when you convert a computer atx power supply into a dc bench supply it can include up to 5 voltage outputs plus a ground. It is intended to provide additional power supply design information not detailed in the atx 2. Any atx power supply can be plugged into the adapter. Note that most schematics circulating on the internet depict oldstyle psu with bipolar transistors and without pfc. Ultra products 400 watt atx power supply quick manual pdf. In very simple terms the psu switched mode transformer has multiple secondaries. Also, for at power supply, onoff of power supply is manually performed. This power supply has atx design and 200w performance. An atx power supply provides a number of peripheral power connectors and in modern systems two connectors for the motherboard. Nov 12, 2019 below is the complete pinout table for the standard atx 24 pin 12v power supply connector as of version 2.
Dec 03, 2012 dc bench supply converted from inexpensive atx power supply the project can probably be completed in a day or so and requires only a few basic tools like a power drill and a few other hand tools. The result is a high capacity power supply that can output 3. In theory an atx12 24 pin connector should also work if you can manage to plug in the connector with pins 1 and in socket and pins 11,12,23,and 24 overhanging the connector. Although it is only a 200 watt early atx psu the description of how it actually works is pretty close to how todays atx psus function. By converting the cheap free atx power supplies that can be found in any discarded computer, you can get a phenomenal lab power supply with huge current outputs, short circuit protection, and reasonably tight voltage regulation on the 5v line. The author is noted usually directly in the schematic.
Although it is only a 200 watt early atx psu the description of how it actually works. When you convert a computer atx power supply into a dc bench supply it can include up to 5 voltage outputs plus a ground. Its construction is typical for a modern computer psu with mosfet switches and active power factor correction pfc. Its easily identified by a warning sticker on the case that reads caution. An evaluation board which works in any standard atx case and uses a standard atx power supply is cheaper to use than one which requires a custom case and power supply. Probably the most common failure that can occur in a computer is the power supply failure, and this is understandable. The best is still using the orginal board for testing. However, you could have one laying around in the form of an atx psu power supply unit. Service manuals, schematics, eproms for electrical technicians. How to add variable voltage to your atx based bench power supply. Here i bring you wiring diagram of pcs power supply of dtk company.
This universal pc power supply tester tests power supplies from both new and old computers. Computer power supply schematic and operation theory. A good power supply is very useful when working with electronics, but it can be pricey. A power supply unit or psu converts mains ac to lowvoltage regulated dc power for the internal components of a computer. Location of a capacitor for suppressing power supply impedance 56 7. This limitation and an initial volume advantage make it more attractive for focussed, costsensitive system platforms. Its a very inexpensive way to make a pretty good dc bench supply or dedicated 12 volt supply for working on projects or powering devices.
How to combine 2 psu, so cheaper and more powerfull h. On this page i collect the schematics of switching supplies for computers smps atx v 1. As you remember, this charger needs at least 17v on input in order to give 350w charging power. Schematic of 300w atx power supply with description keywords. I was drawed diagram, when i repaired this power supply. With the aux 12 volt connector in use now, i would use one power supply to supply the mother board and aux power and the second one for drives and maybe the video card. Power supply design guide for desktop platform form factors. Easy to do repairs of an atx power supply schematics.
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