The mystery of the intermittent fault on flourescent light

[The Ghost]

Change the ballast or whole fitting. Simples

Already done.

 

[The Ghost]

Get suitable access equipment

Absolutely agree there! I have a youngman tower and will be using it for any further access. Just used the ladder wedged at the bottom for a quick look at the fitting adjacent to the faulty light.

 

[The Ghost]

If the lamp is new and good and the endcaps undamaged, I would have changed it by now.

Maybe you meant if the lamp is not new? Anyway the lamp is brand new and so are the tubes. The puzzling thing is that no other lights are affected by this phenomenon on the circuit.

 

[The Ghost]

Would be easier to do that off your ladder

No way! you have one hand to do all the work there is no way you could carry up equipment and tools and then take off the cover, it is a tower job.

 

[Lucien Nunes]

No sorry I missed the 'new fitting and tubes' comment. So what you are trying to discover is whether there is an air-gap in the circuit, or whether some local condition such as temperature is causing any good fitting installed at that point to misbehave. My money would be on an air-gap.

On a related-but-not-the-answer-to-your-problem note, I have experienced 12V DC HF fluorescents misbehave, where turning on one fitting would make another flicker or go off, or it would not light when switched on. They would interact in unpredictable ways, but would also work for days without incident. The fault was life-expired electrolytic capacitors in the inverters, causing them to modulate the DC supply with their switching frequency. As soon as I replaced the caps all were stable. But this is not likely to be the cause here for any number of reasons.

 

[static zap]

Any signs of moisture , dripping ?
( Imagining -COLD)

 

[elsparko]

are the klik roses in a loft area? quite easy for these to get kicked/broken if folk are walking in the loft area and dont look where theyre putting their big clumsy feet

 

[elsparko]

ignore previous comment, picture just loaded lol, quote for a rewire and new fittings, sod messing around with fittings that you didnt even install

 

[ruston]

ignore previous comment, picture just loaded lol, quote for a rewire and new fittings, sod messing around with fittings that you didnt even install

It's ok lol, we will ignore your finger trouble.

 

[elsparko]

It's ok lol, we will ignore your finger trouble.

surgeon says i may get to keep half of it if im a good boy in surgery

 

[static zap]

Lamp changed / cabling not , logically must be in that little bit of cabling.
Phantom enamel painted copper ..
(do they have a night shift - and a fussy sod who hates fluorescent lighting)...even though its HF!

 

[elsparko]

Lamp changed / cabling not , logically must be in that little bit of cabling.
Phantom enamel painted copper ..
(do they have a night shift - and a fussy sod who hates flurescent lighting)...even though its HF!

those baylights can be annoying if they are in the corner of your vision lol

 

[KEV 1 N]

Unlike a choke, which is simple and usually either works or doesn't, an HF ballast is an electronic switched mode power supply, containing many dozens of components (some of which have finite lifespan)

Got some Chryselco 5foot flossys in my loft which my Grandad got donkeys years ago (which were probably old then), they must be 50 odd year old, still working with the Warm White Crompton lamps he got them with and the old aluminium case starters!

 

[Jim90]

Got some Chryselco 5foot flossys in my loft which my Grandad got donkeys years ago (which were probably old then), they must be 50 odd year old, still working with the Warm White Crompton lamps he got them with and the old aluminium case starters!

Surprise the Feds haven't kicked your door in for the lack of snow on your roof in winter!

 

[DPG]

Putting it rather simply, there can only really be two causes:

a) Unreliable supply of electricery to the wires feeding the fitting
b) faulty fitting

You can prove a) by doing suitable testing, but as said above it would need an access tower ideally. I'd at least rope the ladder to the top girder and get someone to foot it at the bottom if not.

You can eliminate b) by changing the fitting - it's possible you have had the initial faulty unit, and then a dodgy replacement.

 

[KEV 1 N]

Surprise the Feds haven't kicked your door in for the lack of snow on your roof in winter!

Haha! My roof usually retains the snow (well insulated) although a few of the neighbours doors require kicking in for "further investigation" due to lack of snow on their roofs!

 

[ipf]

I remember that the very early tubes had an earthed conductive strip along their length to aid starting. I suppose the same capacitive effect is achieved now by internal coatings and the proximity of the tube to its earthed fitting. So check too the connection of the cpc to the fitting, the continuity of the cpc back to the DB and that the reflector is electrically connected to the cpc.

Was that around about the time you were pioneering with radio?
...and that's why some called them 'strip lights', maybe

 

[Marvo]

If I had to work on that ladder I'd be looking for the easiest way out so disconnect ballast and fit LED tubes.

 

[ruston]

I have just done that for the first time this week on a showroom sign.
Up to now I am impressed with them.

 

[westward10]

Absolutely agree there! I have a youngman tower and will be using it for any further access. Just used the ladder wedged at the bottom for a quick look at the fitting adjacent to the faulty light.

Once is enough to become a statistic.