Atx Power supply - The Simplest Way To fix It

Special Review Atx Power supply - The Simplest Way To fix It

I had stopped repairing Atx power provide many years back due to the new one cost very cheap. It's not worth to fix it because the spare parts sometimes were much more expensive than getting a new power supply. Searching for Atx power provide spare parts was not easy as many of them you can't even find them on the internet. Not only that, many complex and dissimilar designed by power provide manufacturers had eaten up our high-priced troubleshooting time too because of we need time to understand how all these dissimilar designed power provide work.

Some of the power provide designs were using the Pwm Ic (Uc3842) and power Fet, some use the double transistors while some use only a single power Ic in the customary side. Because of the manufacturers wants the manufacture to be made into covenant size, many secondary or even customary power provide circuit were build into a modular board (smaller board). This made troubleshooting even more difficult because many times the meter's probe can't reach to the testing point.

The real reckon why I had stopped repairing Atx power provide was the profit margin. If you payment to high the customers rather buy a new unit with one year warranty given. If you payment too low, you may end up in the losing side because of the components replaced, electricity and etc. If you payment reasonable, the profit margin gained can't even cover your time spent on troubleshooting it. I'm here not to discourage you to stop repairing Atx power supply, however if you have the time, have contacts getting cheap power provide components, easy to access many power provide schematic diagrams and etc then you may go ahead to fix it.

Okay back to the article, one of my customers had asked me to fix his Atx power supply. I told him to get a new one (since it was very cheap) but he said he couldn't find one that suits his customer's Cpu. He wanted a power provide that is either same size or smaller then the customary one with same or higher specification but all he could find was a appropriate size power supply!

As a favors to my customer, I would do my best to help him to fix the Atx power supply. When the power provide was switch on, measurements were taken. The results 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 inside was very dirty and I used a vacuum cleaner and a brush to clean off the dirt. Then I saw four filter electrolytic capacitors had bulged at the top casing.

As you know, we as electronic repairers can't just see things at only one side; we have to see the other sides too. What I mean was, try to see if there are any suspicious components that contributed to the failure of the power provide such as broken components, dry joints, loose connection, decay glue and etc before start checking the suspected area.

What I saw was at the customary side there were some components covered with decayed glue as seen in the picture. I have to determined take off it by scrapping off the layers of the decayed glue while preserving the outer layers of the components. Once it was done, I clean it with the Thinner solution. Decayed glue could cause serious or intermittent question in electronic tool because it can be conductive.

If you fix any Atx power supply, make sure you check the fan too because some power provide failure was due to heat caused by a faulty fan. The purpose of the fan is to suck out all the heat generated by the components inside the power supply. In order for the fan to run smooth, you can assistance it by using a Philips oil base spray as shown in the photo.

Once the four electrolytic capacitors were substituted and the decayed glue removed, I then have to plug it into a junk motherboard together with a hard disk to test the operation of the Atx power provide and part all of its yield voltages. It seems like the yield voltages were back to normal. Once everything is okay I then test it in a working Cpu to check for the display.

The reckon I test it with a junk motherboard first as a way not to cause my good motherboard to go bad just in case if the yield voltages is still very high. Good safe than regret later. By the way you can't test a power provide without load otherwise it may turned on for a while and then shut down. If you do not have a junk motherboard you can always at least connect a hard drive and a wire jumper to its connector to turn on the Atx power supply.

Do you know that most Atx power provide is using dual schottky wall rectifiers to convert the ac wave into Dc voltages? Even in Lcd Monitor power supply, a dual schottky were used in the rectification too. For your information, checking schottky diode is dissimilar from checking a normal diode. With analog meter set to X10 K ohms, it should show some leakage reading when doing the reverse bias test. If this component becomes faulty it is very easy to get a replacement, of course you have to get one with the right specification. That's all for today, hope you enjoy the description and come back more often to check out for any newest fix techniques that I'm going to share to you.