Where is my problem with this flourescent lamp?

[Don Klipstein]

In , [e-mail] wrote, edited by me for space:

I have looked at the color of glow produced by many of those. My experience as of the late 1970's was that few produced a neon-like color, and that those appeared to me less-modern-than-usual as of then. I have also seen the glow from the starters built into PL-13 CFLs.

My experience is that most starters produce a lavendar glow of a color close to usual for argon, only a little more whitish.

===================

As much as you appear to me to hate fluorescent lamps, I suspect you might be interested in a characteristic that some starters have. I thought that maybe you would have mentioned this by now. Some fluorescent lamp starters are cranky about starting in complete darkness! Some of those starters are cranky about starting without assistance from the photoelectric effect.

One solution was to add Kr-85 to the gas (or gas mixture) in the starter bulb. But radioactivity got to be politically incorrect. I also see that many aluminum can style starters have a hole in the center of the top of the aluminum can. I wonder if that is to allow one to see whether the starter glows, or to let light into the starter.

[Don Klipstein]

This is a bit of a surprise to me. I have a fair amount of experience with homebrewing and hacking of preheat fluorescent lamp fixtures, and the behavior suggests to me that the starter is re-glowing too easily from the voltage needed to fire the lamp.

This may be from the ballast skimping on current - that can make starting crankier, and then the fixture can get fussier about starters.

You may be able to fix this by using a different FS-2 or FS-2 variant starter, preferably one rated to start 22 watt lamps (along with lower wattages).

Also, proper grounding may make a difference. Did you remove any during your troubleshooting and repair attempt?

Winding a few turns of bare wire around the bulb, over the filaments, has some chance of making the bulb easier to fire. This has to do with capacitive coupling through the glass, so that a very small amount of current does not have to go through the full length of the bulb. That may make the gas in the bulb "break down" more easily.

There is even a remote chance that reversing the leads of the starter will make things better. If ionization in the bulb occurs more easily on one half-cycle of AC than the other due to polarity of the electrode on the "hot side", then reversing the leads of the starter may make a difference. I have seen starters having a polarity when used with DC.

Also try reversing the plug, to reverse hot and neutral, if the plug blades are the same width. (I forget already whether or not you said the plug blades were equal width or not.) And check for hot-neutral reverse at your outlet - that does affect a few cranky fluorescent fixtures.

[Don Klipstein]

One thing to keep in mind: Bad / innefective starters are hard on bulbs, and bad bulbs are hard on starters.

- Don Klipstein ( [e-mail])

[The Daring Dufas]

He could have two problems, a bad starter and a bad ballast. He has eliminated the bulb since it worked in an identical light fixture. Perhaps borrowing the ballast from a known good fixture? It may be a lot work but I would do it out of curiosity.

TDD

[clare]

As a kid I scavenged anything I could find that didn't work and took it apart to find out how it was supposed to work and why it didn't - and fixed it if I could.

Not a whole lot different as retirement looms

[clare]

I think you are describing a mercury vapour glow starter. That would also explain the "silvering" on the glass.

[The Daring Dufas]

Second childhood? It's the freaks like us who will survive when the world goes to hell. I have trouble identifying with someone who's only skill is shuffling papers and doesn't know a hammer from a screwdriver. I get hold of things all the time that were discarded because of some simple, easily repaired problem. I've rescued $100.00 computer motherboards that had a blown keyboard fuse or a kitchen appliance that popped a thermal protector. It never ceases to amaze me about the perfectly good items I find in the trash. My last microwave was left outside a dumpster and it had the manual with it, there was absolutely nothing wrong with the thing. I think someone was moving and tossed a fairly new appliance.

TDD

[Peter]

Don, As far as grounding is concerned, I did not need to remove any special grounding, and replaced everything exactly as it had been, including the foil lined rotating shade, only substituting the cannibalized innards of the FS-2 starter for the glow bulb that I removed. (The original glow bulb did not glow when I applied power. The one from the FS-2 glows lavender). This has become a long thread with multiple side arms. You probably missed some of my previous posts were I stated that the fixture's power plug is 2 prong polarized, and I've checked the wall receptacle with a 3 neon lamp circuit tester designed to detect open grounds, open neutrals, reversed connections, etc. (it checks "correct wiring".

One clue that I failed to mention to date is that the original glow bulb was substantially larger (both longer and greater diameter) than the one from the FS-2. Does that help you make a recommendation to me of which model starter I should purchase and cannibalize to try in place of the one from the FS-2?

[Peter]

Yeah, it would be interesting, but I don't want to investing that much effort. Besides, just my luck I'd break off one of the wires where it enters the sealed ballast unit and end up having to trash both fixtures!

I'm already coming close to my threshold for just giving up. The problem is that these fixtures tend to run $60 - $120 and I'm only using it as a supplemental local lighting source adjacent to my computer table. I'm thinking of just getting a

[bud--]

A starter momentarily shorts across its leads. Hard to remember, I think someone suggested momentarily shorting the leads to see if the lamps light. That should give you a definitive answer of whether the ballast is OK. If that works you could replace the starter with a push button. In some old fixtures that is how the lamps were started - you push and hold the "on" button for a couple seconds and then release it.

If you post the same question to multiple groups use crossposting.

[Peter]

I'll make sure to momentarily short across where I have the starter connected (after I remove it) to make sure the ballast is good, before potentially wasting time/money for a glowbulb from a starter with a higher rating than the FS-2 I tried. However, as you say, it may be easier to drill a hole in the shell of the fixture near the base of the bulb socket and install a SPST normally open push button switch. If so, what voltage and/or current rating should I look for to avoid ruining the switch contacts with normal use?

P.S. I use Mozilla's Thunderbird as my e-mail/usenet client. Thunderbird does not allow cross posting.

[Tony]

I thought my T-bird all ways allows cross posting, I'll test it here.

[The Daring Dufas]

I do it all the time and I use Tbird.

TDD

[Don Klipstein]

The silvering is getter material, simetimes also electrode material sputtered from the electrodes by a high current glow discharge. I remember seeing the spectrum of one of the purplish-glowing starters. I did not recognize the spectrum, but it was definitely not mercury.

[Don Klipstein]

That does not tell me much. I have seen very different shapes and very different sizes of bulbs inside FS-2 starters, depending on their brand and maybe when they were made.

[Tony]

Yep. That's why I always replace the starter when installing a new bulb. Not worth the chance of wasting a new bulb at $5 to $15 when I starter only costs 50 cents.

[Peter]

Follow-up:

I found time last night to snip out the FS-2 innards I tried to use to replace the apparently defective original glow bulb and did the shorting across the starter wire experiment. The lamp lit and glowed normally (no flicker). So, the ballast is good.

That leaves me with either knowing which common starter's glow bulb to slavage, or trying to wire in a push button SPST normally open switch with ?? sufficient rating (to avoid rapidly ruining the contacts).

Again, to summarize, this is a 4 pin rapid start 18W G24q-2 lamp (MaxLite model MLDE 18/41.

[James Sweet]

It's not rapid start if it has a starter, that setup is referred to as preheat start. The lamps designed for one setup will usually work with the other, although lifespan may be decreased.

FS-4 is the higher voltage starter intended for 30-40W T12 tubes, I suspect it will do nicely here. That and the FS-2 are about all you can find easily anymore anyway.

If you go with the button, something rated 250VAC at 1A ought to hold up just fine.

[Peter]

Thanks so much for the correction and the guidance. I think I'll go with the switch. I'll try the FS-4 glow bulb first, as soon as I can get to my local HD. The switch is a more certain fix but there is really no room for it (clearances are very close between the lamp socket and its enclosure, and even if I found room, the socket enclosure and shade have a small radius of curvature and no flat surface on which to mount the switch).

[Archimedes' Lever]

Yes. You become the starter.