I have two adjacent ceiling fixtures holding two 40W 48" fluorescent tubes, both controlled by a wall switch. Sometimes, they go on properly; other times they'll go on if their glass tubes are touched; still other times they need to be rotated slightly in their sockets. And sometimes they won't go on at all.
What should I check?
The fixtures are at least 18 years old, but do not have the little starter cans that older fixtures used to.