PROBLEM
The device was visibly burnt out. Its main microcontroller and several surrounding elements had a completely black and burnt out casing.

SOLUTION
The device was under load to charge completely empty batteries. As this is a difficult task for any charger, and the components of the device itself were already quite old (over 3 years), individual capacitors had short-circuited. Thus they caused major currents that burnt the electrical wires on the PCB itself, as well as the previously mentioned elements.

TESTING OF THE REPAIRED DEVICE

WHAT THE VIDEO SHOWS
The video shows the first trial testing of the charger following its repair. As one can see, the devices works very well, charging half-empty, old batteries.
In testing it is important for the charger to have as difficult a task of charging as possible, which is why old batteries were placed to be charged.