I had stopped repairing ATX power several years back as a result of new one cost very cheap. It’s not worth to repair it as the spare parts sometimes were much more expensive than finding a new power supply. Looking for ATX power spare parts was not easy as most of them you can’t even see them on the internet. Not only that, many complicated and different designed by power manufacturers had eaten up our precious troubleshooting time too because of we want time to know the way each one of these different designed power work.
A number of the power designs were using the PWM IC (UC3842) and power FET, some use the double transistors although some use only a single power IC in the principal side. Because of the manufacturers wants the look to be changed to compact size, many secondary or even primary power circuit were build right into a modular board (smaller board). This made troubleshooting even more challenging because many times the meter’s probe can’t reach to the testing point.
The true reason why I had stopped repairing ATX power was the profit margin. In the event that you charge to high the customers rather obtain a new unit with twelve months 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 own time spent on troubleshooting it. I’m here never to discourage you to stop repairing ATX power, however when you yourself have the full time, have contacts getting cheap power components, easy to access many power schematic diagrams and etc then you can go ahead to correct it. FFPOWER
Okay back again to the content, certainly one of my customers had asked me to correct his ATX power supply. I told him to obtain 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 more specification but all he may find was a typical size power!
As a favors to my customer, I would do my best to simply help him to correct the ATX power supply. When the ability supply was activate, measurements were taken. The outcome were over voltage. The 12 volts line shot as much as 13 + volt and the 5 volts line became 5.6 volts. After the casing was removed, I found the inside was very dirty and I used a hoover and a comb to clean off the dirt. Then I saw four filter electrolytic capacitors had bulged at the very top casing.
Everbody knows, 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, attempt to see if there are any suspicious components that contributed to the failure of the ability 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 principal side there were some components covered with decayed glue as noticed 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 could cause serious or intermittent problem in electronic equipment because it could be conductive.
In the event that you repair any ATX power, make sure you check the fan too because some power failure was as a result of heat the result of a faulty fan. The goal of the fan would be to suck out all heat generated by the components inside the ability supply. In order for the fan to operate smooth, you are able to service it by using a Philips oil base spray as shown in the photo.
Once the four electrolytic capacitors were replaced and the decayed glue removed, I then need to plug it right into a junk motherboard as well as a hard disk drive to try the performance of the ATX power and measure all its output voltages. It appears as though the output voltages were back again to normal. Once everything is okay I then test drive it in an operating CPU to check on for the display.
The main reason I test drive it with a junk motherboard first as a way never to cause my good motherboard to lose their freshness 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 might switched on for some time and then shut down. If you do not have a junk motherboard you are able to always at least connect a hard disk drive and a cable jumper to its connector to switch on the ATX power supply.