I’d stopped repairing ATX power supply a long time back due to the new one cost very cheap. It’s not worth to repair it as the spare parts sometimes were much higher priced than getting a new power supply. Searching for ATX power supply spare parts wasn’t easy as most of them you can’t even locate them on the internet. Not just that, many complicated and different designed by power supply manufacturers had eaten up our precious troubleshooting time too due to we need time to know the way each one of these different designed power supply work.
A number of the power supply designs were utilizing the PWM IC (UC3842) and power FET, some utilize the double transistors though some use merely a single power IC in the primary side. Due to the manufacturers wants the style to be converted to compact size, many secondary or even primary power supply circuit were build into a modular board (smaller board). This made troubleshooting even more difficult because often times the meter’s probe can’t reach to the testing point. FFPOWER
The actual reason I’d stopped repairing ATX power supply was the profit margin. In the event that you charge to high the customers rather obtain a new unit with one year warranty given. In the event that you charge too low, you might result in the losing side because of the components replaced, electricity and etc. In the event that you charge reasonable, the profit margin gained can’t even cover your time allocated to troubleshooting it. I’m here not to discourage you to avoid repairing ATX power supply, however when you have the time, have contacts getting cheap power supply components, easy to access many power supply schematic diagrams and etc then you can proceed to repair it.
Okay back again to this article, among my customers had asked me to repair his ATX power supply. I told him to get 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’s either same size or smaller then your original one with same or higher specification but all he may find was a typical size power supply!
As a favors to my customer, I’d do my best to help him to repair the ATX power supply. When the energy supply was switch on, measurements were taken. The outcome were over voltage. The 12 volts line shot around 13 + volt and the 5 volts line became 5.6 volts. Following the casing was removed, I discovered the inside was very dirty and I used a hoover and a brush to completely clean 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 one other sides too. What I mean was, try to see if you will find any suspicious components that contributed to the failure of the energy supply such as for example 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 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 can be conductive.
In the event that you repair any ATX power supply, make sure you check the fan too because some power supply failure was due to heat caused by a faulty fan. The goal of the fan is to suck out all the warmth generated by the components inside the energy supply. In order 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 to plug it into a junk motherboard together with a hard disk to check the performance of the ATX power supply and measure all of its output voltages. It seems like the output voltages were back again to normal. Once everything is okay I then test it in a functional CPU to check on for the display.
The reason why I test it with a junk motherboard first as a way not to 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 switched on for a time and then shut down. If you do not have a junk motherboard you can always at the least connect a hard disk and a wire jumper to its connector to turn on the ATX power supply.