@carnage4life The working clock uses one of the gears in the broken clock to advance the hour hand, but only on odd numbered days. Also, one of the four AA batteries in the broken clock needs to be hooked up in series to the four batteries in the working clock to increase the voltage slightly, because power is being sent from the new clock's batteries through a resistor in the old clock for reasons nobody understands, but it's definitely true that if you just send the power to the new clock directly, it runs backwards.