I have the following situation and I want your opinion and advice:

==> 1 light switch controlling 1 light fixture with 1 magnetic ballast(120 Vac) and 2 X F96T12/60 W fluorescent tubes.

Problem: Both fluorescent tubes initially light when the light switch is turned on however, after a certain time they both cease to light. Thereafter another few minutes they light up again and the cycle repeats itself on and on (all this with the light switch continually turned on)?

What I did do: I removed the existing magnetic ballast installed on October 10, 1994 (I had written the installation date on it, a habit of mine to see their duration) and replaced it with another "used" magnetic ballast of the same type, however the same problem persists with the replaced magnetic ballast (I have 3 more of these; given to me by a friend who replaced his fixtures of the same type in a storage area with "T-8"s but assured me they all worked)?! What I could add is that the magnetic ballast I removed was so hot that I needed a thick rag to hold it while removing it but there was no visual deterioration like leaking?

Question: Could this problem be related to the fluorescent tubes' contacts/sockets or is this still a magnetic ballast issue like I originally thought?!

Check to be sure the frame of the fixture is solidly grounded, and that the ballast is held in tight with the proper nuts or screws, exactly as manufactured.

Be sure all cable locknuts are tight, and hopefully the cable has a green or bare equipment ground, that is grounded at the beginning of the circuit, and connected to the frame of the fixture, best to use a machine thread screw into a threaded screw hole.

A poorly grounded fluorescent fixture will always operate odd. Hope this helps.