After changing the fluorescent ballast, one bulb works, and the other does not. Any suggestions? I have checked all connections and the bulbs are new.

Answer

Possibly a bad tombstone - the fitting that the lamp fits into. If it is wired correctly and the bulbs are good (you might swap the bulbs to see if the same position in the fixture remains unlit) that pretty much leaves a bad ballast, even though it's new.

Updated on May 10, 2018

Original Article:

How to Replace a Fluorescent Ballast
By Dan Harmon
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