As was said above, a 200 light strand is 4 50-light strands. The 50 light segments are wired in series, but the four sets are parallel; hence why 50 go out at a time, rather than the whole strand.
It's not a fuse problem, since the other sets of 50 are lit. If you've confirmed that all 50 bulbs are good, you're likely dealing with one of three things:
1. A broken wire
2. A bad socket
3. Multiple loose/improperly seated bulbs
Get a LightKeeper Pro, use the shunt repair feature, and if that still doesn't work, use the voltage detector to narrow where the break in the current is.
It's not a fuse problem, since the other sets of 50 are lit. If you've confirmed that all 50 bulbs are good, you're likely dealing with one of three things:
1. A broken wire
2. A bad socket
3. Multiple loose/improperly seated bulbs
Get a LightKeeper Pro, use the shunt repair feature, and if that still doesn't work, use the voltage detector to narrow where the break in the current is.
