how do ballasts fail?

Pre-heat has the electrodes up to thermionic emission temperature before the arc strikes, which is significantly less hard on the lamps than instant start.

In the US, you seem to have spawned a range of different tubes for different control gear, as people work out different solutions to running tubes on 120V. Outside of the US (at least in Europe and other parts of the world I've been to), all T12 and T8 lamps are designed only for pre-heat. Other types of control gear exist, but they are all designed to use preheat tubes.

In commercial premises, lamps which are switched once a day or less mostly fail (or at least become uneconomic) due to phosphor degredation, not failure of the electrodes.

In the case of the 2-D tube the original poster is using, the glow starter is almost certainly integral in the tube base, and it cannot be used with any other type of control gear.

and he charges about $100 an hour. Thats about $200,000 a year.

You wouldn't want him to make less than a decent living.

You forgot to factor in the fact pre-start almost never successfully starts on first interruption. Instant and rapid start lamps are rated from 12K to 24K hours. Pre-start lamps are 6 to 7.5K.

So what? The glow starter keeps on heating the electrode more until it reaches thermionic emission temperature and the arc strikes. It very deliberately doesn't strike before then, as that causes electrode coating sputtering.

This is completely meaningless. I had a computer room full of 8' glow-starter lamps (probably around 200 tubes) which went over

100,000 hours, with probably only 25% failure rate. Trouble was the phosphor was down to well under half light output and site maintenance wouldn't replace tubes until they completely failed to light, but I can assure you nothing about glow-starter limits tube life to anywhere near as low as 7,500hrs. The economic life of the phosphor is limited to perhaps 20-30k hours. If you are switching once per day, the glow starter has no effect on tube life. This assumes you have the correct rating of glowstarter and it is of reasonable quality. Glowstart doesn't work well with very short tubes on 240V (such as the older T5 tubes), because 240V can be enough to start them in cold cathode mode without the electrodes being preheated, which quickly sputters the coating off in the case of frequent switching.

In my garage, I have 3 identical 5' 65W fittings, except that I have replaced the control gear in two of them with instant start (the third is standard glow-start). They are all switched together so ageing is identical, and they get switched quite frequently because there are a number of things in the garage which are frequently accessed. They've been there 3.5 years which isn't long enough for any of the tubes to have failed, but the two instant start ones are showing signs of electrode coating sputtering, whereas the tube with glow start control gear still looks brand new. My guess is the glow start will well outlast the instant start tubes.

You know, many engineers and techs consider flourescent lighting repairs a joke.....You have demonstrated that they are more complicated than many would think. I remember sending a senior tech out to fix one on a piece of equipment...when all was said and done...he needed help. .. So few components but still a specialized field as many fields are in electronics!....take care Andrew, Ross

That's a decent living. My cost (fully burdened) is well above that number. It's a nice wage, but not spectacular.

Dear Mr. S

See

Ain't that the truth. Uncle replaced his old 'glow-starter' style with a newer 'rapid-start'. Darn thing wouldn't work right. Only would 'light' if he touched the tube or the frame after switching on. That's when his nephew (me) had to explain that when the instructions say the fixture frame must be grounded, there's a *reason* for it. Problem solved.

daestrom

nothing...........Did

Hey bush...how ya doing? I'm with Keith here...If I go into a job my charge is $250 minimum whether I am there a half hour or an hour and a half....Though, if its something simple (10 minutes), I comp it and tell them next time I charge.... The cost of a vehicle, insurance, equipment, years of experience and the posibility of complications warrants it... Have a great one there bush man! (hmmm...maybe I should reword that huh!)

And I thought I charged a lot. Up here on this mountian most computer consultants are glad if they can get $25 bucks an hour. I stopped doing it as it just did not pay.

I guess large companies might be able to afford $250 bucks but I do not think most normal people can. I just had my dishwasher fixed. It was $65 for the service call, applied to the labor fee if a part had to be replaced. But for that the guy had to drive about 100 miles round trip, up a 6000 foot high mountain. Of course he tries to batch his calls so he calls on two or three people in one day.

I have a Maytag and boy did they try to screw me. I had it about 2 years and it has had 4 repairs in that 2 years. I called the Maytag factory and they checked the date I bought it and told me they were going to give special consideration and only charge me half for the parts. Well the repair man came, told me I needed a new motor water pump, He told me it was out of service contract but that the parts were gaurenteed for 5 years so the moter water pump which is about the whole machine would cost me nothing. I told him what the factory had said, and he said, boy were they trying to screw you.

No more Maytags for me or any one in my family. By the way, he also told me that about 1/3 of the Maytag washers that come into his store (and they are the major Maytag distributors in my region) come in not working. So much for Maytags vaunted reliability.

I'm with you on the Maytags....I have a washer that likes to walk across the room if the load is not "perfectly balanced". And it is leveled correctly too! The repair guys used to say they were "Maytagging it" on slow days....I guess that one is gone. I guess you figured out that the consumer electronics business doesn't pay as well as industrial electronics. If you have a million dollar line down, and it's costing you 10 bucks a minute...Well, they will pay anything to get it going. It's not difficult to make $1000 a day if you are good at industrial automation and own your own business! So Happy Holidays there bushman....Ross (I still should think about re-wording that!!)

Perhaps I should go back into industrial electronics. I had a friend who had a stamper stamping out metal parts. The problem is that sometimes the machine would not full eject the part and then come down again. That would jam the machine and they would have to clear it before they could start it again. So he had to have some one sit there and press the button. The machine knocked out a part every second revelution of the fly wheel.

Well I made him an electric eye that detected the part as it passed out of the range of the stamper. Still had a guy sitting there feeding the machine, but now the eye caught the part coming out so quick that it tossed out a part every revelution. Doubled production and no jams. He was a buddy so I did not charge him any thing.

A couple of days later a huge truck pulled up in front of my house and off loaded about 40 sheets of 4X8 beutifally finished plywood panels which which I refinished my garage into a finished room . The stuff was worth close to a thousand dollars. I should have taken the hint then.

I used to work for Teledyne. They had a line down that was producing about 40 million dollars worth of power supplies for some gov equipment. They thought it was ripple but it was an oscillation. I discovered the problem was the op amp required a resistor after it when driving a capitive load ir ut would oscillate. Took about two days to fix the problem, (Soldeir a real small 1/10 watt, 100 ohm resistor on the board. on the output of the amp. They were so pleased with my solution as it got the line going better than every, and every supply they built now passed inspection, that about 2 months later they laid me off.

Layoffs are always on the horizon...sometimes the guys on the top don't know who the contributors are!! Have a Great Holiday Bushdabee....Ross

They new ross. A vp and the vp of engineering had changed jobs so the new vpe wanted his own guy in. They went down the tubes as a result.

But they did offer me a job elsewhere, to far from home makeing drones.

Well I can tell you that if the written quote/diagnosis looks like it was written by a second grader, you are not credible in my eyes and if you've got the original poster's attitude, you're definitely getting my business.

Are one of you guys the infamous AHOLE from Alt.home.repair? The supreme hemorrhoid of the Internet? That oozing pustule of tile slingers? Is that you old Arty Boy? If not, you sure do a good impression of him.