Road sign light starting

[amtrakuk]

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?

[Nick217]

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

[AngryHorse]

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

[amtrakuk]

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

[eclipsislamps]

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.

[Kev]

Could of even been volt drop!

[amtrakuk]

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.

[versalift09]

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.

[BC5-80]

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.