Hi, I have an old TCP 15 watt CFL that has been in service for a few hours every day for a very long time now. It has certainly lived up to its advertised lifespan and I know it's approaching EOL. Lately, it has started doing something that I find interesting. It will randomly go dim. Sometimes it will come back up to brightness after a few seconds, but it will often stay dim. Here's where it gets interesting (to me at least). If I disconnect the bulb and smack it (even if I do this several hours later), it will let out a quick flash (the first time it did this from putting it down after I had replaced it, and it peaked my curiosity to try it again). If I continue to smack it until it stops flashing, then power it back on, it will work fine. Sometimes for hours.

I'm far from an expert in how these lamps work, but the fact that the lamp will flash without power means that something is storing power. Typically, from my experience with electronics (I mostly work on audio, video, PC, and video game electronics), that would be capacitors, but I don't know if anything else in a CFL can store charge. So I'm curious if this could be something like the soldering to a capacitor going bad (so smacking it bridges the connection temporarily), an actual capacitor failing, or something totally different, perhaps something that would normally allow the capacitors to drain.

Thanks for your time!