I have a 2-tube, 8' flourescent ceiling fixture. Recently one of the tubes went out. Replacing the tube did not help. So I replaced the ballast. Now neither side will work. I have carefully checked the wiring visually. Both old and new ballasts were (are) for 6-8' T12 tubes.
Any advice, such as how to check the lamp with a VOM, would be appreciated.
You more than likely wired it wrong. For the next time this happens and one bulb goes out...switch the bulbs and see if the problem goes with the bulb. What kind of bulbs do you have? Which ballast did you use? There are a lot of combinations out there...you may have made the wrong ballast choice. Pictures may help if you can provide.
Do you want it your way or the right way?