How to diagnose and replace a failed pc power supply wikihow. Hardly anyone actually repairs power supplies anymore. The last item you should test before popping the hood. Of course, like any good troubleshooters and according to the pcb troubleshooting flowchart we gave the power supply a good visual inspection. Robert mammano, a cofounder of silicon general semiconductors, develops the first integrated circuit for smps control, model sg1524. Well while working with electronics i felt the need for a dc bench power supply, and that is when i found on the net to convert an atx to dc power supply, so thought of repairing my old one. Dec 03, 2004 troubleshooting power supply problems. For further learning of the technique of repairing psu equipments please refer to the books by mr. The best is still using the orginal board for testing. Here i would like to share another article with you that talks about how i have solved a slightly.
Power supply troubleshooting power supply and chassiscase. Switchmode power supply troubleshooting safety the primary danger to you is from the input side of the supply which is directly connected to the ac line and will have large electrolytic capacitors with 320 v or greater dc when powered often, even if the supply does not work correctly and for some time after being unplugged especially if the power. Therefore i to need to get the atx power supply working first. Unfortunately you can not just have the wires left open, luckily both of these issues are easily fixed. However, brand name manufacturers, especially older dells, often used proprietary power supplies and made up their own color coding, so i wouldnt throw out a power supply that supplies 5v where you think it should supply 3.
Jestine yong who made a well explained repairing guides with great pictures and explanations. Some atx power supplies have an overflow switch while others do not have them. To determine if the power supply is functioning properly, start with procedure 1 and continue with the other procedures as instructed. Troubleshooting a switching power supply part 1 circuit.
But since i had no equal 400 watt supply and i needed my pc badly to finish my work, i decided to use an older 300 watt atx supply instead. Here in the uk, and also in the usa, if a standard at or. The basics t he power supply is a large metal box, mounted inside the pc that provides power to the motherboard and various peripherals. Highefficiency 255 w atx power supply reference design. Computer power supply troubleshooting replacing power unit. Well might be youll have to replace your atx power supply but wait, dont throw the old supply away cause you can still get it to work.
The simplest version, as with this athlon system, is the standard atx. In this ebook, you will learn all my advance troubleshooting and repairing secrets. For atx power supplies, the specification requires that voltages must be within 5% of the rating, except for the 3. Troubleshooting and repairing atx power supply brought to you by jestine yong i hope that you have enjoyed the short report of the easy way to understand switch mode power supply. This manual was originated from switching power supply user manual published in. Nov 09, 2015 but since i had no equal 400 watt supply and i needed my pc badly to finish my work, i decided to use an older 300 watt atx supply instead. The power supply converts the wall electric power of 120v or 240v ac into different dc powers. May 23, 2019 with the power off and unplugged, try toggling the switch to 230, then back to 115 to make sure it is seated in the right position.
Jul 19, 2001 learn to troubleshoot power supply problems. View and download ultra products 400 watt atx power supply quick manual online. The most important power connections in any pc are the motherboard connections. How to use an old atx power supply as a lab power supply without modification. I have found normal diodes will fail prematurely and as such are unacceptable as substitutions. Most of the time, it is simply easier, safer, or less expensive considering the time and materials involved to replace the power supply rather than to repair it. Use this computer troubleshooting guide to help diagnose and perform computer repair on your pc. Computer power supply troubleshooting atx pc power supply. Atx300p4pfc pc power supply sch service manual download. The more you work on repairing power supplies, the easier it gets. An interface box was created to connect to the standard atx power supply connector to allow turning on the power supply and access to the various voltages.
To read the rest of the chapter of troubleshooting and repairing switch mode power supplies 271 pages, please visit. Power supply standardization how pc power supplies work. Im just glad to see a resource that describes methods for repairing ps modules. Computer power supply troubleshooting atx pc power. Installing a new power supply is one of the easier repairs to make. Switching power supply technical manual adm instrument. Specifications the design closely follows the atx12v version 2. If a fan has failed because of a short circuit or incorrect input voltage, you will not see. The pc power supply is probably the most failureprone item in a personal computer. Power supply repairtroubleshooting, testing, problems and. Now we can begin actually replacing the old power supply connectors with connectors from the new power supply. Typical symptoms associated with powersupply failures include the following.
With a few simple tools and the help of this guide, you can do this job yourself and save. And today the 26 of october i was finally ready to check the inside of this switching power supply. The color scheme used for each voltage in the 24 pin connector holds for the other atx standard power supply connectors. If you want to join us and get repairing help please sign in or sign up. Prior to atx, the power switch was directly connected to the power supply and the computer cannot turn itself off. An annotated schematic of 250w atx power supply with active power factor correction \pfc\. I am trying to repair a 500 watt cooler master psu. Easy way to understand the 11 circuit functions of smps. It heats and cools each time it is used and receives the first inrush of ac current when the pc is switched on. Power supply troubleshooting pc repair and maintenance. Some of them have an extra connector for power management, some are designed for a desktop chassis, and others are for fullsize towers. It also provides practical, useful procedures to follow when you are troubleshooting switchedmode power supplies. Ultra products 400 watt atx power supply quick manual pdf. If you get stuck in repairing a defective appliance download this repair information for help.
Ultimate computer troubleshooting guide and diagnostics. Figure 41 shows a typical desktop computers power supply. Power supply troubleshooting power supply and chassis. Replacing a power supply illustrated how to replace an. You can have them all by reading the smps troubleshooting manual available via the site below. Sun, 09 dec gmt jestine yong switch mode pdf jestine yong reserves the right to use the full force of. Sep 08, 2019 how to diagnose and replace a failed pc power supply.
Typically, a stalled cooling fan is a predictor of a power supply. Home atx power supply repair pc atx psu quick repair. How to use an old atx power supply as a lab power supply. Computer techs will use a multimeter to test for proper voltages. It is very common for service centers to simply replace the entire power supply board or module even if the problem is a 25 cent capacitor. Learn to troubleshoot power supply problems techrepublic. And later on when i had more time i would check if i could repair the now defect 400 w atx supply. For atx power supplies, the specification requires that voltages must be within 5% of the rating. Dont waste anymore of your precious time to search from the internet to learn the basic repair.
Apr 25, 2010 if you are not getting power, or if your system randomly reboots or develops bizarre symptoms that you cannot nail down, consider swapping in a new power supply. Troubleshooting and repairing atx power supply by jestine yong free download as pdf file. If you are not getting power, or if your system randomly reboots or develops bizarre symptoms that you cannot nail down, consider swapping in a new power supply. Spending too much time trying to performing power supply troubleshooting could become expensive, as unexpected dip in power can damage other computer parts, such as the hard drive. Service manuals, schematics, eproms for electrical technicians. Reliable power supply maintenance, management, troubleshooting, and analysis the power grid is the single most important piece of infrastructure in our society, and regular maintenance and management are essential in order to prevent problems. Troubleshooting and repairing atx power supply by jestine yong. Generally, the problem is a blown fuse or a tripped circuit breaker. No indicator lights are visible, with no disk drive action and no display on the screen. Whether youre new to designingin a power supply or dcdc converter or an old hand, this.
Power supply troubleshooting and repair tips youtube. With a few simple tools and the help of this guide, you can do this job yourself and save on expensive repair. How to convert atx psu pc power supply unit into a cheap bench top power. I found that i would a bench power supply to do other projects or electronic devices.
In addition, some atx power supplies have an exterior fan that fits under the power supply. Secrets on power supply repair and troubleshooting solving problems and failure in switch mode power supplies. When you consider that many power supply repairs are effected with the replacement of a single diode, you can see that they are anything but disposable. Its quite a beast and would set me back a considerable amount new, so id like to see if i can fix it. The super capacitor powers the ad300 motor to the correct power fail position, secure or unsecure, during a power fail event. Atx is an industry specification that means the power supply has the physical characteristics to fit a standard atx case and the electrical characteristics to work with an atx motherboard. To open downloaded files you need acrobat reader or similar pdf.
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. Second, check the overflow switch on the back of the power supply. Understanding and troubleshooting the pc power supply. I got a measurement on my psu tester on the 5vsb between 3. Isolate hardware, such as the motherboard and power supply. Tips on repairing smps power supplies without published schematics. Secrets on power supply repair and troubleshootingsolving problems and failure in switch mode power supplies. Notes on the troubleshooting and repair of small switchmode.
To open downloaded files you need acrobat reader or similar pdf reader program. As mentioned earlier, replacement power supplies are available from many manufacturers. Feb, 2020 how to use an old atx power supply as a lab power supply without modification. You dont need to use the ps914 power supply with 9002q board, you can simply use the ps902 power. The power supply the power supply at and atx are the two types of power supplies that can be installed in any pc the atx form factor motherboard, with its unique atx power supply, dominates todays systems all power supplies share a number of common features such as the power connection, motherboard power, power.
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. Repairing the power supply power supply and chassiscase. Essential guide to power supplies 1st edition xp power romania. Switching power supply technical manual adm and mean well. Instructions for performing atx smps troubleshooting, using the light bulb tactics, voltage testing procedures, a great deal of pointers and solutions, plus almost a dozen of switch mode power supply repair case studies for you to benefit from. Typical symptoms associated with power supply failures include the following. Nov 01, 2000 some atx power supplies have an overflow switch while others do not have them. Of course, at the same time make sure that your cat or dog didnt play a trick on you and unplug the power supply. The older 8712q card that was used on ps873 power supply will not work with ps914 power supply. 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. Atx boards also introduced the soft off capability. This book covers switchedmode power supplies that you may encounter in modern consumer electronic products, and focuses on the most common supplies found throughout the industry.
Troubleshooting the power supply basically means isolating the supply as the cause of problems within a system and, if necessary, replacing it. Its fan spins only for seconds and stop, which is caused by defective capacitors. Having said that, repairing a power supply yourself may in fact be the only economical option. We recently received a switching power supply that failed in the field so we took the opportunity to do some troubleshooting and discuss the process here on. Computer power supply troubleshooting the power unit is one of the main parts of a computer system, which is responsible for supplying the required power to the whole pc system components. When power supply issues are caused by factors such as equipment malfunctions or. Feb 14, 2014 troubleshooting a broken power supply. Feb 06, 2011 switched mode power supply repair guide. I have an 800w atx power supply given to me by a friend because it doesnt work any more. How to diagnose and replace a failed pc power supply.
This is outside of the tolerance table and makes the mistake. Pc atx psu quick repair electronics repair and technology news. I converted a atx power supply to a bench power supply lately after spending 15 some hours. The power supply repair is one of the most challenging tasks for an electronic repairer and once you have mastered the circuit and repair technique, to troubleshoot other types of circuit such as the color, vertical, audio, high voltage and so forth will.
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