Electronic question plz help???

Question

An electronic circuit consists of 48 decorative 5V lamps all connected in series to a 240V source as shown below.

Lets assume that the circuit worked properly but stopped working after it was moved to another location. When plogged in at the new location, all lamps fail to switch on.

all i need is all the condition that can possible cost this circuit to not work ???

Answer 1

As all the lamp are connected in series, breakdown of any one will break the chain.

therefore may be any one or more of lamp may be fused

Answer 2

1. One or more of the lamps has blown

2. One or more of the lamps not screwed / plugged in properly

3. The fuse in the plug has blown

Answer 3

old power source was 240 and new power source is not. that might make it stop working

Answer 4

1. one or more lamps loose during transportation.

2. one or more lamps filament open .

3. one of the lamp socket wire was broken internally.

4. new location does not has power in the outlet.

To trouble shoot: 1. use voltmeter to measure the outlet,make sure the correct voltage existed or test it with a 40 watts light bulb. 2. make a pair of isolated jumper has two sharp pins. With the power is plug in,short each 5v lamp one by one (trouble assume if only one lamp was open in the whole series circuit). Lamps will light up when you short the open lamp. 3. Still fail to locate,take down all the lamps,measure each lamp with ohm meter,it shall show at least 30 ohms or more.