The Lamp Room

Was waiting in the car just as the light above a Give Way sign lit. Odd thing, it seemed to pulse the tube in ever quicker pulses like a SON starting, over about a minute. The tube appeared to have lit but the pulses still continued. I thought fluorescent sign lighting used a ballast and starter or do they used some pulse starter?

Could be anything in those! Sign lights are the most unloved things out there!

Sounds like a cold tube?, what size was it?

There seemed to be 2 tubes above a Give Way sign so I'm guessing 2 x 8 watt. Just seemed odd that the tubes seemed to be lit and steady for a few seconds then started the starting cycle again

Sounds like a tube that was just starting to fail, seen it happen many times before. The electrode still has enough emmitter on to keep the tube lit for a short time until it drops out.

Could of even been volt drop!

I guess the pair of you could be right. I was thinking of some starting mechanism that blindly pulsed the tube X number of times regardless of its running status and then checked with a resistance check across the electrodes or something.

This sounds like the minicell on the sign is gradually switching as opposed to switching straight on. This could be an old thermal cell or just a modern electronic one that's going a bit tits up lol. I've had this on SELC 101TF cells before.

I would guess a defective light sensing switch with no hysteresis, so switching unnecessarily at threshold. I bet it's an electronic version, though, not thermal. I've had two thermal cells controlling our outside lighting since the early 90s and they've never faltered once.