The 6 foot tube in our 30+ year kitchen fluorescent light has started to blink. The tube is about 10 years old, so due for replacement, although it wasn't showing the tell-tale darkened ends.
I replaced it with a Crompton 70w tube but this started to blink. "In my opinion it's the starter that needs replacement" said the salesman. Problem is, this unit doesn't have one, is this possible?
I removed the tube and the 6' white concave reflector from above the tube but no sign of a starter. Instead, there's a 9" x 1" x 1" (from memory) white plastic box, which carries the mains wiring.
Any thoughts on where the starter can be located or are some fluorescent units ...... starter-less? TIA
30+ years old suggests 2 as the most likely. So I'd open that box & see if it has a starter wired directly in, or whether the ballast is electronic. After disconnecting power of course.
Bad connectors to the end of the tube can also cause flicker, though not commonly.
How many wires go to the plastic box? If it is a coil which would need a starter there may just be two. My electronic ballasts have atleast 6 wires, two for each end of the tube and two for the mains input. The electronic starters I bought a few years ago have worked well.
There are rapid start fluoros that do not use starters,some of the tubes for these have metallic paint strip along the full length some have earthed metal reflectors in close proximity to the tube
Its an electronic quickstart probably, and the whole unit will need to be changed. They seem to sort of lose their high strike voltage after a time, never unpotted on but they tend to start when working rather as if it was on a dimmer, but when they stop working they just flicker but a bit faster than the starter kind and without the little 'ting' noises. Brian
Well the ones in our old Studio wre 1980s and one went and needed just an electronic ballast fitting. Of course never managed to get a direct replacement but nothing a few self tapping screws could not sort out. N I know for a fact that you could get 12v small lights with electronic ballasts so I guess these were just more powerful ones, but of course on the mains you only need to generate the breakdown voltage but if the transformer inside has some shorted turns or the controlling device is leaky then the result is flickering. Have you thought of going down the led route? Brian
Phoned a large lighting retailer (Beacon Plymouth) and was told :- "tube blinking, the problem is with a) the tube, b) the starter or c) the choke". When I described the wired 9 x 1 x1" unit, he confirmed it was the choke and they have a lifetime of approx 4 replacement tubes or 15 years. So I can't complain after 30 years use. When I replace the whole unit, I'll put up a picture of the choke, in case someone Googles.
The LED equivalent of a 70w fluoro is 26w. Beacon sells a 6' unit for £39 but the tubes are not replaceable, it's a sealed unit, throw-away job.
Agreed, LCD is the way forwards but as the choke is a bit dodgy, I won't spend £24 on a separate LCD. The Deltech is also a sealed unit but at 35000 hours, should see me out :-
formatting link
The following is available in single or double and the tubes seem to be replaceable :-
formatting link
Advert on same page has the tubes selling at £12. Thanks to all those who contributed, I'm now a lot wiser on fluoro's.
A couple of weeks ago I was in uk.d-i-y posters loft (wave to Terry Casey) and found a fluorescent light with a starter but no choke. I think I took a photo. I would say that it was 30 years old.
Actually "Quickstart"(tm). The technology is now over half a century old (predates 1972 at any rate). Essentially it's an autotransformer with tube heater taps at each end which is connected across the tube with a conventional magnetic ballast in series with the mains supply.
The ballast and transformer can be a combined high leakage transformer arrangement that does effectively the same function but I've only ever seen and used the separate ballast and transformer setup. There's no separate starter switch and the tube lights up in some 250 to 300ms after switch on with no flicker (about as fast as a 12v 35W halogen on a 60W rated electronic ballast "transformer").
The theory of operation is that the "Quickstart" transformer runs at close to full mains voltage delivering heater voltage (10 volts or so) which causes the thoriated filaments to reach full heat and emit a copious supply of electrons, allowing the tube to strike without the stress of positive ion cathode stripping bombardment to boost the filament to temperature. Once struck, the tube current drops the voltage down to just over 100vac, reducing the heater current voltage which continues to help run the filaments at a more optimal temperature than simply relying on tube current alone.
Tubes last far longer in luminaries fitted with the classic "Quickstart" circuit, especially when subjected to frequent switching cycles, typically lasting their full design life of 7 to 15 thousand hours to the
80% of design lumens cut off point in spite of frequent switching.
Unfortunately, the new mercury starved T8 tubes can't be started by this classic circuit so once your T12 tubes supply has been used up, you're looking to upgrading to an electronic ballast or else taking the pragmatic option of a retro-fit LED tube where you'd be well advised to remove the QS transformer at the very least if not the transformer and ballast itself.
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