December 3, 2022

TX Power Supply – The best way Vehicle Them

I’d stopped repairing ATX power many years back as a result of new one cost very cheap. It’s not worth to fix it as the spare parts sometimes were much more costly than finding a new power supply. Trying to find ATX power spare parts was not easy as many you can’t even see them on the internet. Not only this, many complicated and different designed by power manufacturers had eaten up our precious troubleshooting time too as a result of we need time to understand how all these different designed power work.

A few of the power designs were using the PWM IC (UC3842) and power FET, some use the double transistors while 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 as well as  CN505 power station primary power circuit were build in to a modular board (smaller board). This made troubleshooting even harder because often the meter’s probe can’t reach to the testing point.

The actual reasons why I’d stopped repairing ATX power was the profit margin. In the event that you charge to high the customers rather buy a new unit with 12 months warranty given. In the event that you charge too low, you could end up in the losing side due to the components replaced, electricity and etc. In the event that you charge reasonable, the profit margin gained can’t even cover your time used on troubleshooting it. I’m here to not discourage you to prevent repairing ATX power, however if you have the full time, have contacts getting cheap power components, easily accessible many power schematic diagrams and etc then you might go ahead to correct it.

Okay back again to this article, one of my customers had asked me to correct his ATX power supply. I told him to obtain a new one (since it absolutely was very cheap) but he said he couldn’t find one which suits his customer’s CPU. He wanted a power supply that’s either same size or smaller then the original one with same or older specification but all he could find was a standard size power!

As a favors to my customer, I’d do my best to help him to correct the ATX power supply. When the power supply was switch 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 found the within was very dirty and I used a vacuum cleaner and a brush to completely clean off the dirt. Then I saw four filter electrolytic capacitors had bulged at the very top casing.

You may already know, we as electronic repairers can’t just see things at only one side; we’ve to see one other sides too. What I am talking about was, make an effort to see if there are any suspicious components that contributed to the failure of the power 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 have been some components covered with decayed glue as observed 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 absolutely was done, I clean it with the Thinner solution. Decayed glue may cause serious or intermittent problem in electronic equipment because it could be conductive.

In the event that you repair any ATX power, be sure you check the fan too because some power failure was due to heat the result of a faulty fan. The purpose of the fan would be to suck out all heat generated by the components inside the power supply. To ensure that the fan to perform smooth, you can service it with 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 in to a junk motherboard together with a hard disk drive to try the performance of the ATX power and measure every one of its output voltages. It seems like the output voltages were back again to normal. Once everything is okay I then test drive it in an operating CPU to test for the display.

The reason I test drive it with a junk motherboard first as an easy way to not cause my good motherboard to go bad just in case if the output voltages is still very high. Better safe than regret later. Incidentally you can’t test a power supply without load otherwise it might fired up for a time and then shut down. If you do not have a junk motherboard you can always at the least connect a drive and a line jumper to its connector to turn on the ATX power supply.