I am trying to repair a Bosch battery charger for a 14.4 volt cordless drill. For whatever reason, it does not charge the battery and I feel that if I can open it, I may be able to repair it. However, to open this thing takes a screwdriver in the shape of a triangle. I have checked all the hardware stores and can not find a triangle screwdriver. This is more than likely a specialty tool, anybody know where I can find such an item?