AKA Percussive maintenance. Sometimes, things in older flashlights aren't all aligned or for some reason the circuit just can't complete, so you smack it on yo

AKA Percussive maintenance. Sometimes, things in older flashlights aren't all aligned or for some reason the circuit just can't complete, so you smack it on your hand and it ... just works. Unless the batteries or bulb truly are dead. Then you just have a sore hand that you can't see.