The switch mechanism cracked in my magnifying lamp. No ballast. Just a momentary and a latching switch combined, that feed the 4 terminals on the tube. The equivalents I find are around $20. Must be a cheaper source. Physical shape doesn't matter much, since the hole can be enlarged.
Thanks.
That's a special purpose switch that combines the function of a glow-starter and on/off. Not a common hardware store stocked item. I've an old 15" tube desk lamp like that and it has an inductor (coil) ballast in the base. Are you certain yours doesn't have an inductor or electronic ballast? I've never seen a fluorescent lamp fixture without one. As for the bum switch - one alternative to a new switch would be to wire in a glow switch, space permitting, and replace the defective switch with just an on/off one. You might have to extract the glass envelope glow switch from its plastic or metal can. You'd also have to determine the current rating of the required glow switch. Sincerely,
-- J. B. Wood e-mail: arl_123234@hotmail.com
A ballast is inevitably present.
NT
I had to replace the switch on my bench magnifier lamp (long ago swapped-out lens with an ex-epidiascope bulging lens for bigger mag), normal switch. Does have ballast in the base and a starter "lamp" but I wonder if excess current makes the switches fail more than usual.
Mpfffff.... replace the silly lamp with an LED kit (there are half-a-dozen out there) for about the cost of that switch. And be done with it.
Peter Wieck Melrose Park, PA
I'll look. Thanks.
There could be something in the base, but it's hard to open. It does look like the power cord goes all the way to the top so I assumed there was nothing in line.
Alternatively, can you add a starter that allows use of a plain switch?
yes if you can fit it in there somewhere. Glowstarters are widely available, perform poorly but work. The glowswitch is far smaller than the plastic container. A relay with brief time delay makes a much better starter.
NT
Great recommendation.
Are those designed to work in series with a ballast?
Some do, some come with a bypass that fits into the starter socket. Depends on which you choose. I prefer the latter as the system is more simple in place. But that option costs a buck or two more.
Peter Wieck Melrose Park, PA
Hello, and I have to take issue with your "perform poorly" remark. Glow switches (aka "starters") have been around for decades and are very reliable. And if they're reliable and work, how do they poorly perform?
In a traditional fluorescent lamp (hot cathode type) fixture with a coil ballast the lamp may pulse a few times before the gas discharge path is established. The ballast performs the functions of both a current limiter and providing a temporary voltage boost to establish the gas discharge path. When the glow switch disconnects after the lamp filaments have been heated there may not be enough of a voltage boost to fire up the lamp because of when this occurs on the AC cycle. Usually no more than a couple of start repeats are required and that's why the lamp pulses. In any event glow switches are quite reliable and cheap to replace when required. Sincerely,
-- J. B. Wood e-mail: arl_123234@hotmail.com
tch is far smaller than the plastic container.
they greatly reduce the life expectanc of tubes and are unpleasant on the e ye during starting.
Not so. For a project I tested the strike rate using switch contacts instea d of a glow starter. It was 100%. The reason glowstarters extinguish the la mp is purely because they're horrible glowstarters - excluding the few case s where the lamp extinguishes itself due to it failing.
NT
Why? Waste? Your? Time?
what is the fascination here with moribund or already dead horses? By shift ing to 'modern technology' - at least in this case - not only is one reduci ng landfill (however many mercury-containing lamps) but reducing energy use d and increasing reliability. A cheap thing that one uses 10 of is not so c heap as that bit-more-expensive-thing that one uses 1 of.
The fixture in question is not a valuable museum-piece, but a tool. And the idea is to continue using it as a tool, rather than tossing it into landfi ll.
Peter Wieck Melrose Park, PA
Nope - some cooker hood lamps just have a big resistor.
You can get electronic starters, I was quite impressed. The muppet electrician that fitted a "D" luminair in the bog, fitted the wrong ballast - it took ages to strike from the get go and after a week, it was turn the bog light on, go for a cuppa and wait for the light to come on. The electronic starter still took a while, but it just blinked on instead of 10 mins flickering. An electronic ballast was about the same price as a tube on eBay and lasted a while - but I bodged it with a bunch of candle style LED bulbs rather than go through all that crap again. LED GU10 lamps are also an option - and much better chance of getting cool white.
...acting as a ballast. Let us know if you have something useful to add.
Yeah, I'll get one of those. But what will I do with the new tube I bought A*WEEK before the damn switch went? FRAK!
Of course the new tube was only $10.
Hello, and I fail to understand what you mean by "horrible". That glow starters are old technology is understood but they're still cheap, reliable, and in most cases easy to replace. That isn't to imply that I would use them in a modern design with other choices such as electronic ballasts/starters and cold-cathode lamps being available. And of course we can go with LEDs as another poster mentioned.
One thing I didn't mention describing the starting process is filament-heated cathode temperature at the instant the glow switch opens. I would presume the lamp requires higher boost voltages between the cathodes to establish the gas discharge path when the cathodes are cooler. That makes startup more dependent on where on the AC cycle current through ballast coil is interrupted by the starter. Since the glow switch is a relatively fast-acting device the combination of cathode temperature and ballast-provided voltage boost frequently isn't sufficient to establish steady-state lamp operation during the initial start attempt. Replacing the glow starter with a momentary-contact pushbutton most likely enables the filaments to heat the cathodes to an optimum temperature for starting and thus more likely start the lamp first time. Sincerely,
-- J. B. Wood e-mail: arl_123234@hotmail.com
witch is far smaller than the plastic container.
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stead of a glow starter. It was 100%. The reason glowstarters extinguish th e lamp is purely because they're horrible glowstarters - excluding the few cases where the lamp extinguishes itself due to it failing.
As I said:
he eye during starting.
as I already explained, my experiment & product showed that guess to not be the case.
NT
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