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Old 17th Jan 2019, 5:38 pm   #81
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Default Re: The demise of the fluorescent tube

I have two circular fittings, must be well over 40 years old and still going strong. They take a 400mm diameter 60W tube. I only have one spare tube left, maybe I should stock up with some more if I can find them. I like the light as there are very little shadows with these.
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Old 17th Jan 2019, 6:23 pm   #82
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Default Re: The demise of the fluorescent tube

60 watt circular fluorescent tubes are still readily available. A quick look on ebay shows a number of sellers offering them at about £10 each, cheaper if buying several.

I rather like these old circular fittings, some types used two lamps of different diameters, to give more light, or a choice of lighting levels via selective switching.

I also recall circular fluorescent fittings with a central GLS lamp. Sometimes found in cinemas and theatres with the GLS lamp being connected to a central battery emergency lighting system.
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Old 17th Jan 2019, 7:06 pm   #83
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Default Re: The demise of the fluorescent tube

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Originally Posted by Paul Stenning View Post
When it stopped working the customer would have to somehow work out which part needed replacing, find and purchase that (if still available), fit it together and hope for the best. Chances are they would buy the wrong part, or a different brand or lumen level and it wouldn't fit or wouldn't work.!
Exactly: we've been through this cycle historically/economically and have sensibly arrived at the point where the 'consumer interface' is the lampholder.

You fit a 'bulb' into your MES/ES/BC/GES/GU10 lampholder or your fluorescent-tube-housing, switch on, and for 99% of consumers it 'just works' - so everyone goes home happy.

I'd truly hate for this perfected convenience and efficiency to be spoiled in the name of 'greenness'. It's only a lightbulb - life's surely too short for anyone to want to re-introduce complexity here!
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Old 17th Jan 2019, 8:03 pm   #84
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Default Re: The demise of the fluorescent tube

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If I could find a long term reliable LED lamp I would be happy to spend a bit more, all so far are the same cheap construction and component quality. Poundland do good 5W ones that (so far) have outlived some £8 Philips ones.
That 'trap' seems to be the case in a number of products, particularly stand alone halogen electric fires and car tyre pumps. No matter how much you pay they all seem to basically be unreliable poorly built Chinese units.
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Old 17th Jan 2019, 9:46 pm   #85
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Default Re: The demise of the fluorescent tube

A shame, the Chinese can and do make bloomin' good stuff (Apple for example) and probably the Poundland lamps.
 
Old 17th Jan 2019, 10:13 pm   #86
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Default Re: The demise of the fluorescent tube

There are not that many parts in an LED lamp: the LEDs, the dropper capacitor, the bridge rectifier, the smoothing capacitor, the discharge resistor, the LED ballast resistor and the surge limiting resistor. The main "lifetime determining" components are the LEDs, the dropper capacitor and the surge limiting resistor. Rectifiers are pretty reliable anyway, the ballast resistor should not be overstressed unless one or more LEDs fail short, if the smoothing capacitor loses capacitance or goes leaky the lamp will begin to flicker -- and if the discharge resistor fails, you won't notice anyway until you remove the lamp from its holder!
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Old 18th Jan 2019, 12:33 am   #87
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Default Re: The demise of the fluorescent tube

More modern LED lamps generally contain more sophisticated circuitry than that.
They often contain a switched mode power supply with a constant current output, this runs the LEDs optimally despite variations in line voltage, line frequency, and LED voltage which is temperature dependant.

The difference between the switched mode type and the capacitive dropper is easily determined be a simple test if you have a variac.
Reduce the voltage by say 15%. The switched mode LED will maintain constant light output, and draw more current at the reduced input voltage.
The capacitive dropper type of LED lamp will become dimmer at the reduced voltage and will draw less current.

The switched mode lamps are usually rated for actual supply voltages from about 264 volts down to 200 volts, some types down to 90 volts.
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Old 18th Jan 2019, 12:59 am   #88
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Default Re: The demise of the fluorescent tube

With CFLs, by time the lighty-up tube bit was tired and blackened, the cheapest-bid electrolytics in the base were likely on their last legs, the plastic packaging of the HV HF transistors would be hardened and brittle from heat-cycling, the cheapie film resistors would be on borrowed time, the PCB was probably toasted and dry-jointed.... Easy to justify an all-together disposable package from both manufacturing convenience and consumer confidence point of view.

Do high-efficiency, high-brightness LEDs go weary and dim with time? We've probably all got stuff with 30 or 40 year-old indicator LEDs that still seem fine, but I wonder if more recent and highly energy-dense lighting-type stuff has a more limited best-performance life? I can imagine that some transparent packages might get a sort of cataract effect from intense photon flux eventually, or that other effects could come into play.

Regarding separation of illuminator and electronics, I certainly recall the case of one 4-pin 10W CFL and electronic ballast- when the illuminator eventually blackened and failed to start, I plugged in an apparently very similar 10W unit of another make. Result- a minute or so of disappointingly dim and flickery light followed by a loud pop and a stream of smoke. Admittedly, I hadn't exhaustively researched compatibility but it's the sort of thing that the proverbial man-in-the-street could be excused for.
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Old 18th Jan 2019, 2:16 am   #89
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Default Re: The demise of the fluorescent tube

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Originally Posted by julie_m View Post
The main "lifetime determining" components are the LEDs, the dropper capacitor and the surge limiting resistor.
The main life limiting factor in the LED globes we have is the diodes used in the bridge rectifier (yes, individual diodes in ours) and lead free solder.

They get so hot they melt the (poorly applied) solder and drop off the pcb.
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Old 18th Jan 2019, 10:10 am   #90
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Default Re: The demise of the fluorescent tube

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It's only a lightbulb
I agree, but the trouble is, everyone has a few. I'm sure many people have said about incandescent lamps 'It's only a lightbulb' after tens of decades of satisfaction. But look where we are now!

There's a cost to everything and like it or not, the emphasis is on the environment. Reconciling cost of manufacture, longevity, the impact on future sales from 'everlasting lamps' and the cost presented to the consumer to get them sold in the first place isn't easy.

Incidentally, the 4' fluorescent tube in our utility room is twenty three years old and hasn't failed yet. It's on at some point every day and its light has been cast on three tumble driers and three washing machines.
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Old 18th Jan 2019, 10:16 am   #91
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Default Re: The demise of the fluorescent tube

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The difference between the switched mode type and the capacitive dropper is easily determined be a simple test if you have a variac.
Reduce the voltage by say 15%. The switched mode LED will maintain constant light output, and draw more current at the reduced input voltage.
The capacitive dropper type of LED lamp will become dimmer at the reduced voltage and will draw less current.
Is this all that differentiates a 'dimmable' LED lamp from a non-dimmable one, then?
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Old 20th Jan 2019, 3:25 pm   #92
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Default Re: The demise of the fluorescent tube

Hello, the kitchen tube failed over Christmas which was a bit of a problem
found out that Screwfix stock them,so all was well The best colour rating is 840 which is daylight, So stock up while they are availabe, BQ Alo have them in quantity
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Old 20th Jan 2019, 3:43 pm   #93
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Default Re: The demise of the fluorescent tube

I replaced the 4ft fluorescent lamp in our kitchen (12 years old) simply because it seemed impossible to get a replacement tube locally. So after a trip to one of the big 'sheds' I came back with a 4ft LED replacement. It is so bright that there must be something like 3x the light of the old tube. To be honest it's nearly too bright as a one-for one replacement. My wife now complains of headaches brought on by the interaction of flicker between the new kitchen LED light, and an older LED fitting at the other end of the room.
This does not seem to flicker on it's own, but run both lights and the effect is quite unpleasant. I used an iPhone 7+ camera in slo-mo mode and this really shows up the switching. The older LED lamps really flicker this way, but the new striplight LED appears almost 'constant'. The colour of the new light is very 'cold' much more towards blue. The manufacturer also state that
'should this fitting fail there are no replaceable parts inside' cough up another £30.00 I suppose. I wonder if it will last 12 years? SJM

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Old 20th Jan 2019, 4:25 pm   #94
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Default Re: The demise of the fluorescent tube

For a new lighting need in a newly built or fully refurbished house, I would select an LED light fitting.
For an existing and still serviceable fluorescent fitting I would be inclined to simply replace the failed tube, buying at least one for immediate use and a second long term spare.

A newly installed lamp and another unused spare should in total last for at least 10 years, and possibly for 50 years.
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Old 20th Jan 2019, 5:47 pm   #95
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Default Re: The demise of the fluorescent tube

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The manufacturer also state that
'should this fitting fail there are no replaceable parts inside' cough up another £30.00 I suppose. I wonder if it will last 12 years? SJM
And that is what has put me off fitting LED lighting in my house. No, not my objection to replacing more than necessary, but :

The stated life of said LED fittings suggests (with the sort of use I would give them) they might last 10 years. More likely 5. Now I don't mind having to replace a 'bulb' every few years ('bulb' here includes fluorescent tubes, LED replacements, etc). It's a simple plug-in job that takes a few minutes. But if I have to replace the entire fitting then most likely an exact replacement will not be available. Meaning I will have to re-drill the ceiling and maybe repaint it. In any case it will take a lot longer than a few minutes.
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Old 20th Jan 2019, 5:53 pm   #96
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Default Re: The demise of the fluorescent tube

"Buying another tube to keep as a spare" always assumes you have somewhere safe to store it. Keeping a spare fluorescent tube in the cupboard-under-the-stairs or similar probably means it will end up being broken before it's needed. Having a spare also somehow mystically ensures that the one in-service will now last forever so your spare is never needed.

Also consider the 'opportunity cost' of your spare - what else could you better have used that money for rather than tying it up in a spare?

My parents were in the habit of doing this 'buy one extra as a spare' thing: when they died and we did the house-clearance all these largely-unidentified 'spares' cluttering the utility-room and attic went in the skip, because the things they were the spares-for had long since been disposed-of anyway.

I really must work out how to dispose of the unused CFL bulbs I have here - a 'gift' from British Gas a couple of decades back, when they were on one of their energy-efficiency drives. I dread to think how much this dented their profits. Charity-shops don't want 'em.
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Old 20th Jan 2019, 5:59 pm   #97
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Default Re: The demise of the fluorescent tube

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I really must work out how to dispose of the unused CFL bulbs I have here - a 'gift' from British Gas a couple of decades back, when they were on one of their energy-efficiency drives. I dread to think how much this dented their profits. Charity-shops don't want 'em.
The giving away of CFL's was because it was the cheapest way of the energy suppliers to meet energy saving/efficiency targets, and so whilst it cost them money it was cheaper than the other options. Also remember that when they were doing this I believe CFL tungsten replacements were government subsidised and you could pick up the bulbs extremely cheaply (10p a bulb?).

As for disposal you local tip/household recycling centre should take them.
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Old 20th Jan 2019, 6:04 pm   #98
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Default Re: The demise of the fluorescent tube

Many thanks to you all for the info in this thread. I had not realised the fluorescent tubes in my workshop posed a risk with the two small lathes I use from time to time. One query though - did the UK have a panic over some of the components of the holders? - (fluorocarbons or something either in the starters or the ballast resistor) Here in NZ there was mass horror at this and heaps of fluorescents were trashed thanks to it. That's how I ended up with 5 or so double fitting and umpteen tubes for free.
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Old 20th Jan 2019, 6:26 pm   #99
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Default Re: The demise of the fluorescent tube

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And that is what has put me off fitting LED lighting in my house. No, not my objection to replacing more than necessary, but :

The stated life of said LED fittings suggests (with the sort of use I would give them) they might last 10 years. More likely 5. Now I don't mind having to replace a 'bulb' every few years ('bulb' here includes fluorescent tubes, LED replacements, etc). It's a simple plug-in job that takes a few minutes. But if I have to replace the entire fitting then most likely an exact replacement will not be available. Meaning I will have to re-drill the ceiling and maybe repaint it. In any case it will take a lot longer than a few minutes.
Yes, I had this dilemma with a new extension . Part of me wanted to fit recessed LED ceiling panels, but for the reason you state, I opted for 2 roses of 3 GU10 spots, to which I fitted LED bulbs. If I could be sure of some sort of standard for LED panels, I would have certainly gone with that option, but it all seemed like the wild west and I really don't want to be lumbered with serious remedial work in the event of failure.
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Old 20th Jan 2019, 7:02 pm   #100
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Default Re: The demise of the fluorescent tube

LED lamps are sort-of repairable -- you can get the LED modules and the power packs online. Some of them even have individual replaceable diodes, though there is a definite trend towards COB -- Chip On Board -- construction. Of course it's a question of how bothered you can be, given that a whole new fitting probably won't cost much more than mending your existing one.

I think it's fairly inevitable for some sort of standard to emerge eventually, because everyone will want to be compatible with the major brands' offerings. And I don't think standard push-and-twist lampholders are going away anytime soon, either.
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