Heating, Cooling and HVAC

Humming and flickering lights mean the ballast is worn out:-

STEP-1.Snip the old ballast wiring several inches from the end of the ballast with a side-cutting pliers or wire snips. Cut all the wires connected to the ballast.

STEP-2.Unscrew the ballast-mounting nut and drop the old ballast free (the ballast will have either one or two mounting nuts). Hold on to the ballast with your free hand to keep it from falling out.

STEP-3.Mount the new ballast in the fixture. Strip the electrical wiring back 1/2 in. and connect the matching-colored wires with twist-wire connectors

STEP-4. Tip: Take the old ballast to the store with you.

STEP-5. Compare the new and old ballasts to verify that the wiring diagrams, voltage and current match before installing the new ballast.

Source:The Family Handyman