I’d stopped repairing ATX power a long time back due to the new one cost very cheap. It’s not worth to fix it because the spare parts sometimes were much higher priced than finding a new power supply. Looking for ATX power spare parts wasn’t easy as many of them you can’t even find them on the internet. Not just that, many complicated and different designed by power manufacturers had eaten up our precious troubleshooting time too because of we need time and energy to know how all these different designed power work.
A few of the power designs were utilising the PWM IC (UC3842) and power FET, some utilize the double transistors while some use merely a single power IC in the primary side. Due to the manufacturers wants the design to be changed to compact size, many secondary or even primary power circuit were build into 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 true reason I’d stopped repairing ATX power was the profit margin. If you charge to high the customers rather purchase a new unit with one year warranty given. P2001 power station If you charge too low, you could end up in the losing side due to the components replaced, electricity and etc. If you charge reasonable, the profit margin gained can’t even cover your own time allocated to troubleshooting it. I’m here to not discourage you to avoid repairing ATX power, however if you have the time, have contacts getting cheap power components, easily accessible many power schematic diagrams and etc then you might proceed to repair it.
Okay back once again to this article, certainly one of my customers had asked me to repair his ATX power supply. I told him to obtain a new one (since it had been very cheap) but he said he couldn’t find one that suits his customer’s CPU. He wanted a power supply that’s either same size or smaller then a original one with same or maybe more specification but all he may find was a standard size power!
As a favors to my customer, I’d do my best to greatly help him to repair the ATX power supply. When the power supply was activate, measurements were taken. The outcomes were over voltage. The 12 volts line shot as much as 13 + volt and the 5 volts line became 5.6 volts. Following the casing was removed, I found the inside was very dirty and I used a hoover and a brush to wash off the dirt. Then I saw four filter electrolytic capacitors had bulged towards the top casing.
You may already know, we as electronic repairers can’t just see things at just one side; we have to see the other sides too. What I mean was, try to see if you will find any suspicious components that contributed to the failure of the power supply such as for instance broken components, dry joints, loose connection, decay glue and etc before start checking the suspected area.
What I saw was at the primary side there were some components covered with decayed glue as seen in the picture. I need to carefully take it off 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 due to heat caused by a faulty fan. The purpose of the fan is to suck out all heat generated by the components inside the power supply. In order for the fan to perform smooth, you can service it using a Philips oil base spray as shown in the photo.
After the four electrolytic capacitors were replaced and the decayed glue removed, I then need to plug it into a junk motherboard together with a hard drive to check the performance of the ATX power and measure most of its output voltages. It seems like the output voltages were back once again to normal. Once everything is okay I then test drive it in a functional CPU to check on for the display.
The main reason I test drive it with a junk motherboard first as a way to not cause my good motherboard to go south 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 turned on for a time and then shut down. If you don’t have a junk motherboard you can always at the very least connect a hard disk drive and a cable jumper to its connector to switch on the ATX power supply.