I had stopped repairing ATX power many years back as a result of new one cost very cheap. It’s not worth to correct it as the spare parts sometimes were much more expensive than finding a new power supply. Trying to find ATX power spare parts wasn’t easy as most of them you can’t even find them on the internet. Not just that, many complicated and different created by power manufacturers had eaten up our precious troubleshooting time too because of we want time for you to know the way each one of these different designed power work.
A few of the power designs were utilizing the PWM IC (UC3842) and power FET, some use the double transistors though some use merely a single power IC in the principal side. Because of the manufacturers wants the design to be made into compact size, many secondary as well as primary power circuit were build in to a modular board (smaller board). This made troubleshooting even more challenging because often the meter’s probe can’t reach to the testing point.
The real reason I had stopped repairing ATX power was the profit margin. If you charge to high the customers rather obtain a new unit with 12 months warranty given. If you charge too low, you may result in the losing side because of the components replaced, electricity CN505 power station and etc. If you charge reasonable, the profit margin gained can’t even cover your own time used on troubleshooting it. I’m here never to discourage you to avoid repairing ATX power, however if you have the full time, have contacts getting cheap power components, accessible many power schematic diagrams and etc you might go ahead to repair it.
Okay back to this article, among my customers had asked me to repair his ATX power supply. I told him to acquire a new one (since it had been very cheap) but he explained he couldn’t find one which suits his customer’s CPU. He wanted a power supply that is either same size or smaller then a original one with same or higher specification but all he could find was a regular size power!
As a favors to my customer, I would do my best to help him to repair the ATX power supply. When the power supply was turn on, measurements were taken. The outcomes were over voltage. The 12 volts line shot up to 13 + volt and the 5 volts line became 5.6 volts. After the casing was removed, I discovered the interior was very dirty and I used a vacuum and a brush to wash off the dirt. Then I saw four filter electrolytic capacitors had bulged towards the top casing.
Everbody knows, we as electronic repairers can’t just see things at only 1 side; we’ve to see another sides too. What After all was, try to see if you will find any suspicious components that contributed to the failure of the power supply such as broken components, dry joints, loose connection, decay glue and etc before start checking the suspected area.
What I saw was at the principal side there have been some components covered with decayed glue as noticed in the picture. I need certainly to carefully eliminate it by scrapping off the layers of the decayed glue while preserving the outer layers of the components. Once it had been done, I clean it with the Thinner solution. Decayed glue might lead to serious or intermittent problem in electronic equipment because it may be conductive.
If you repair any ATX power, make sure you check the fan too because some power failure was as a result of heat the effect of a faulty fan. The objective of the fan is always to suck out all heat generated by the components inside the power supply. For the fan to run smooth, you can service it by using a Philips oil base spray as shown in the photo.
When the four electrolytic capacitors were replaced and the decayed glue removed, I then need certainly to plug it in to a junk motherboard as well as a hard drive to test the performance of the ATX power and measure every one of its output voltages. It looks like the output voltages were back to normal. Once everything is okay I then test drive it in an operating CPU to check on for the display.
The reason why I test drive it with a junk motherboard first as a way never to cause my good motherboard to go bad in case if the output voltages remains very high. Better safe than regret later. In addition you can’t test a power supply without load otherwise it may fired up for a time and then shut down. If you may not have a junk motherboard you can always at least connect a hard disk drive and a cable jumper to its connector to turn on the ATX power supply.