Step 1: Caution: Mains Voltage!
Before attempting anything similar with mains voltage, it is crucial that you understand the risks involved in working with mains voltage. If not handled properly it can cause serious injuries and even death.
Step 2: Pre-check the Fault
The power supply I'm gonna repair is a 5 volt supply from an Android TV Box that stopped working suddenly. When I plug it into the box, it flashes the LED for a fraction of a second and then it turns off.
I measured the voltage on the end with no load and it showed the expected 5 Volts on the output but as soon as I connected any load, the voltage dropped to around 1.5 volt so I knew that the fault is somewhere on the output side.
Step 3: Open the Enclosure
To open the case, there is a screw on the top and once opened, you need to push on the case tabs to open the case.
Step 4: Find the Issue
Looking at the back of the board, there was nothing obvious but as soon as I flipped the circuit, there was a capacitor that was fully blown out of its case.
Step 5: Replace the Broken Part
I found a replacement and with the soldering iron I first removed the broken one, I've cleaned the solder pads and I installed the new one making sure to keep an eye on the polarity. Fortunately for me the polarity was clearly marked on the top of the board but if you are doing a similar repair on an unmarked board, you will need to be more careful.
To solder the capacitor flush with the board, you can add solder first to one of the pads without too much attention of the positioning. After that, you can reheat the solder and push the capacitor from the other side. After the soldering was done, I've cut the legs of the capacitor and then mounted everything back together in the case.
Step 6: Enjoy Your Fixed Power Supply
This was an easy straightforward fix that is really typical with such power supplies. Capacitors often fail over time so be sure to check yours for any bulging, cracking or a complete separation as in my case.
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