I have been using these FC12 T9 Circline 32w fluorescent bulbs for many years. https://www.lowes.com/pd/GE-32-Watt-12-in-4-pin-Circline-4100-K-Cool-White-Circline-Fluorescent-Light-Bulb/3400530
The bulb just burned out, as usual with blackened ends. But my spare bulb won't light properly. Only the first 1-2 inches lights, and the other end merely glows yellow. When I flip the 4-prong plug, both ends then light only 1-2 inches. My other spare bulb behaves the ~same. So either (1) the ballast is bad, but not dead, or (2) both spare bulbs are from a bad batch.
The ballast was working just fine every day before the bulb burned out, not slow to light up and always consistently good. It was a very humid and rainy year, btw.
The fixture is roughly 4 years old. The previous fixture lasted probably over a dozen years, but then again things are made these days to fail quickly. It seems less expensive to buy a new fixture than to buy just a replacement ballast (with $10 flat rate shipping, plus the problem of whether it will fit). The ballast is square-ish like here: Ballast TLE54 won't light 2 circline bulbs
The spare bulbs are unused but around 2 years old. This says they don't degrade over time: Fluorescent bulb shelf life
No, I don't want LED. Is there a way to test without ordering and waiting for a new fixture? I could buy a new bulb as a test, but then if that won't light then I have 3 unused bulbs on hand and still have to then order and wait for a new fixture.
Might Phillips bulbs (HomeDepot) be better than GE (Lowes), or do they all just come from the same mega-factory in China?
[edit: I have uplugged/re-plugged many times, in case the connectors had acquired a coating]