Thank goodness Santa brought a gift early this year -- the chaps over at EDN magazine published a nifty circuit that lets you find the culprit in both series-string and alternating-series-string lights before you drive yourself crazy. Or Christmas is ruined. Here's another bum light test circuit, with instructions helpfully translated from Dutch. After you've found the bad bulbs, good luck finding replacements for them. This year, my husband wound up buying new light strings after striking out at several stores. Maybe it's a conspiracy!