- Plug lights into an outlet
- Remove an unlit bulb
- Plug the empty bulb socket into the Lightkeeper Pro
- Pull trigger 20 times while watching for faint flickers coming from the other unlit bulbs. This is the culprit bulb.
- Replace the culprit.
This method doesn't always work, but today it worked for me with 2 of 2 strands. Visit the LKP website for the official user instructions and also for alternate methods of fixing broken lights. Email me with questions.
Note: this is not a paid endorsement.