I took my old fluorescent tube with me to Lowe's/Home Depot today to compare it to the 15" tubes there... my old tube was a 15". So, I bought a new tube and took it home to install in my machine. Naturally, it didn't want to light up. It glowed at the ends, but would never arc all the way across. If I rotate the tube slowly, I was able to have a moment where the tube lit all the way across. But as quickly as it lit, it would quit. So, I decided to check the starter. There was an FS-5 installed, but according to the starter it was not intended for a 14 watt bulb. So, I made another trip to Lowe's to purchase a new starter. I came home with an FS-2 that indicates it is for a 14 - 20 watt bulbs in 15", among other, lengths. I plugged in the new starter, but my bulb's performance is only marginally better. It will light up further across the tube but will not arc all the way across. Again, if I rotate the bulb slowly I find a point at which the bulb arcs all the way across. Now, however, it will remain on for several seconds before it begins to flicker and eventually goes out.
If I allow the bulb to remain in the position where it only lights part way across from each of the ends it will remain on (in a continually flickering, partially lit condition).
Do I need to replace the ballast?