A mate of mine has a pacemaker fitted. One day when he was walking in the park the device failed and he was in a bad way.
Just by chance a Japanese man came to the scene, saw what had happened, and said maybe he could help. It turned out he fitted car radios, and opened his case to reveal countless radio parts. He did some measurements with a multimeter then replaced some of the parts with items from his stock! SUCCESS, the pacemaker was working again and my friend recovered quickly!
He's still doing OK.....except that when he goes under a bridge you can't hear what he says!