One day my loyal fake iMax B6 charger stopped working. Instead of beginning to charge it beeped ferociously and showed this message on the display:
I unscrewed the 8 screws on the sides of the box and opened the charger. At first I noticed that it was wet inside. There were traces of water and the screws connecting the PCB to the bottom plate were rusty! I marked them in the image below.
I didn’t know how it became so wet but I figured it must have stood near an open window while it was raining outside.
Except for the rusty screws everything seemed to be ok and the display was working fine only it wasn’t charging, so at first I couldn’t find the problem. But then a friend of mine saw that the left resistor at the bottom right side looked burned, as you can see in the next photo.
To verify that this is the problem we measured the resistance of the resistor and found it is very high (we couldn’t tell what it should be because the color stripes lost their original colors). We figured that it couldn’t get so hot and burn if the resistance was meant to be so high.
My friend explained that this resistor is probably acting as a fuse. So I went to my favourite store in Belfast (Northern Ireland) – Maplin Electronics and bought an assortment of low resistance resistors for about 4 pounds (I bought two of each).
I soldered the 3W resistor in place of the burned one:
And here is a photo from the top. You can also see in this photo that the charger is charging again at 3.9A.
I just hope that the resistor on the right will not burn since there in no place for an additional resistor of the size that I bought …