Up until 1946, when Christmas lighting production resumed after World War II, by far the most popular style of electric Christmas lights in use were the series wired type, which meant that if one bulb failed, the entire string went out. Many a frustrated decorator was often relegated to dreaded "search and replace" duty, spending the better part of a December evening searching for that elusive burnt out lamp. Covered on this page are some industry attempts at solving this most frustrating problem...
Apco brand series light tester, designed to make finding a burnt out lamp a bit easier. The user was to grip the wires coming from the light socket firmly with the device, which would puncture the covering of the wires and short out the socket. If the string lit, the the defective lamp was found, if not, then the user would proceed to the next socket and so on. This device added greatly to the fraying problem frequently found with series wired lighting sets.
Thanks for the link -- I could browse through this sort of stuff all night and have added it to my favorites to go back and look at in depth!
I have many years' worth of memories of playing "hunt the blown bulb" on light strings. Fancy electronic chaser lights and such like have become popular in recent years in Britain, but the old series chain is probably still the most common. Our chains are usually twenty 12V lamps for 240V operation.
The bulbs are supposed to short out when they blow to keep the rest of the chain alight, but it doesn't always work out that way.
#151989 - 08/08/0311:21 AMRe: If ONE Goes Out They ALL Go Out
A non-contact voltage probe often works to find the blown bulb. Hold it against the glass part of the bulbs, work your way along the string to find the last bulb that make the probe beep. This is the blown bulb.
#151990 - 08/08/0311:32 AMRe: If ONE Goes Out They ALL Go Out