Do photoelectric controls go bad?

Factual Questions
1

I wonder at what point a topic is to esoteric for here?

Maybe someone that knows more electronics than me can answer. I recently complained about a sodium vapor street light near me that was cycling on and off, as is typical for aging lamps. I happened to see them when they were there, and to my surprise they replaced the twist on photocell as well as the lamp. So do these things go bad? They are socketed, but is that for ease of replacement when they fail, or so they don’t have to have two models of luminere, one with a photocell and one without?

And would a typical failure mean cycling on and off, as opposed to failing either on or off. I’m wondering if they replaced it because it could fail in that matter, on the off chance the cycling was due to the photocontrol and not the bulb, or if they just have a policy of replacing older photocells while they’re at the fixture for any reason, so if it does fail on or off next month they don’t need to make another trip out there.

2

Yes they go bad, especially when kept outdoors. The photocell might be fine, but any other part of the module could get corroded, dirty, etc. also. They may also replace the photocell when they perform anyother service on the unit as you suggest. Not sure exactly what type of configuration they have, but it’s possible they changed the bulb type requiring a different control module.

Most common problem I see around here is in the fall when wet leaves get stuck on a street light covering the sensor so the light never goes off.

3

Lamp cycling could be a failure of the photocell module, so they would probably replace everything they could (including ballast) just to avoid a return trip.