The fuse F1 on my brush gets blown when I turn it on. When replaced, I can charge the brush, all LED come on and U2 IC gets super hot. I assume this one drains a lot off current, tripping the fuse. I can’t find any information on what the IC is. On my toothbrush that IC has IU2FJ on it, another has IU2GG on it. I was looking for a 6 pin TSOP IU2 IC, but can’t find anything. I assume is some kind of power management IC.