I haven't repaired the 24V electronic ballast, and I have repaired a lot of the 220V electronic ballast. The most easily damaged component of 220V electronic ballast is the resonant capacitor connected in series with the filament, which is easy to break down and short circuit. The phenomenon after breakdown is that the filament is red but the lamp tube cannot be started, which will also seriously burn the fuse. In addition, the filter capacitor is prone to leakage, which is a serious "Explosicum". The damage of the filter capacitor will mostly burn out two rectifier diodes and fuses. Transistors are also cracked, and the way of damage is more complicated. Under normal circumstances, if all the transistors are blown up, this board has no repair value.

It is a little expensive to add fuse or safety resistor to 220V ballast, but the most commonly used cheap ballast has no safety components, only a thin wire (printed on PCB) for overcurrent protection, and the effect is very bad.

Ballast fault can easily lead to overcurrent, and fuse burning is common, so it is impossible to judge whether it is caused by abnormal voltage.