One day I went to use my $150 toothbrush, only to find that it was completely dead. After basic troubleshooting it was determined to not be a failure of the induction base as using the travel charger would not help. To the internet I went and found a few leads. The batteries seem to only last for 1-2 years. There were several posts about people repairing the cheaper $100 toothbrushes, but not the higher grade Diamond toothbrush. I acquired the toothbrush in better financial times however a mortgage payment and upcoming wedding prevent me from dropping a quick buck on a toothbrush. Battery replacement resulting in working toothbrush, but only for a short time as something is causing the battery to discharge. I noted a 620 ohm resistor getting very hot upon installation of new battery. Inside the brush is a PIC16 microcontroller.