Hello
As Orochimaru wrote, the easiest way is to measure whether there is a passage between the adjacent pins of the fluorescent lamp, but the more important thing is its tightness, whether the gas inside the tube has not escaped. Because you can easily light a fluorescent lamp cold, i.e. by powering it from two opposite pins. If you see that at the twisted pairs (ends) the fluorescent lamp is quite blackened, it's better to leave it alone, it will shine weaker and there is a good chance that it will fail soon. Electronic ballasts that ignite the fluorescent lamp cold, or such converters for fluorescent lamps powered by a battery, accumulator or other low voltage source (although in this case there are also such converters that require connecting 4 leads, i.e. whole twisted pairs), work well with a fluorescent lamp with burnt-out strands. If you use a traditional fluorescent lamp power supply system (choke and igniter), then a fluorescent lamp with burnt strands is useless.
