How I Have Repaired My CellPhone Charger- By Beh
Input is 220 volt/50hz AC output is 4.9 vDC
The problem with my cellphone charger was that it had stop charging the battery of mycellphone. I have decided to fix it on my own with the help of Jestine Yong Power Supplyrepair book- TROUBLE SHOOTING AND REPAIRING SWITCH MODE POWER SUPPLIES.
The charger cover was opened and I’m confident that it can be repaired. The first thing I havechecked was the output voltage with a voltmeter. It reads zero volt which mean there was a serious problem in the charger.
It was quite difficult to open the cover because the chargerdesign does not have any screw. I left no choice and had to use a hammer together with a knife to force it open.
After opening the cover I could cleary see that this charger design was a double sided circuit board. The top parts were all conventional parts like bridge rectifires, filter caps, optoisolator ic ,mosfet, transformer, and shottky diode and the bottom circuit were all SMD components such as resistors and transistors.
I began to check on the conventional components first and I found a resistor with the value of 10 ohm 1 watt was completely open and this low ohm resistor acts like a fuse. Beside the fuse, one of the four bridge rectifiers diode was shorted and the part number was 1N4007. I did checked on other parts like capacitors, transformer, Mosfet, schottky diodes and etc were all good.
I believe the shorted rectifier (diode) drained too much current causing the low ohm resistor to open circuit thus preventing more components to burn. After replaced the two components, thecharger started to work again. The cover was sealed with the help of glue. The cost of repair was only USD 0.5 cents! A new normal charger would cost USD10.00 and the original one is more expensive-USD50.00 probably. I hope this article can be helpful to those who wants to repair their own cellphone charger.
Mr Behzad
Iran
Note: Please do not attempt to perform the repair work if you do not know about electrical safety.
If you have any interesting repair article that you want to share to others please do email me.
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