Just had a dream where I spotted a multi story high school building resembling a skyscraper with many 4 lamp F40T12 preheat halfpiper fixtures all over the place with many even installed outside. Many of the outdoor halfpiper fixtures were stem mounted while the halfpiper fixtures that were visible indoors from windows were all flush mounted. Some of the outdoor halfpiper fixtures were installed on a canopy over the main building entrance while other outdoor halfpiper fixtures were installed in outdoor corridors. The outdoor halfpiper fixtures had a mix of blackender and brassender F40 tubes installed. The indoor halfpipers were turned on while the outdoor halfpipers were off. Later on in that dream, I caught the building undergoing renovations and saw a large number of the halfpipers laying on the ground underneath the main entrance canopy with tubes and PCB-laden 2 lamp brick ballasts removed. As the renovations were going on, I loaded roughly 25 stem mounted fixtures onto a flatbed truck along with the removed brick ballasts. I felt a little sad as the dream ended because I sadly did not get the fixtures that I have been rescuing in that dream. Some of the tubes that I salvaged in that dream included a large number of F40WW and F40CW tubes, but sadly, some F34CW tubes were mixed in.

The white coating on both ends is typically universal burning . Here in the U.S. A base up only lamp has the coating only on the base end while on a base down only version it's only on the crown end of the arc-tube .

I think you have that inverted, a position redistricted metal halide lamp will *generally* (but not always looking at you GE Halarc!) have its white coated arc tube end at the lowest point in the lamp



for example note in the Lamp from Max that I Linked to,

https://www.lighting-gallery.net/gallery/displayimage.php?pos=-154383

its burning position is base up only, and notice how the white part of the arc tube is in the crown end of the lamp, as when the lamp is base up that is the lowest point in the lamp


and conversely on this base down burning lamp https://www.lighting-gallery.net/gallery/displayimage.php?pos=-230971

note how the white part of the arc tube is now near the base of the lamp since when burning base down, that is the lowest point of the arc tube



the whole point of the coating is to raise the temperature of the coldest part of the arc tube and ensure thermal uniformity of the arc tube for most optimal performance, and to simplify it, as most of us know heat rises, so thus the lowest part of the arc tube is what needs the most insulation




also with regards to the first line, certain lamps for horizontal burning only will still have heat reflective coatings on both ends of the arc tube, just something to be aware of


so the heat reflective coatings of a metal halide arc tube, can give you a good hint as to the burning position of the lamp, but one should still be on their toes about it if that makes sense

The white coating has nothing to do with burning positions, it's purely a heat reflecting coating to raise the cold spot temperature behind the electrodes. The lamp will almost certainly be universal burning, but without a picture of it, it's not possible to say definitively.

thats very misleading, the white coating, has *everything* to do with the burning position of a metal halide lamp


I recommend giving these uploads by Max a read as to the importance of the white coating, and its influence on the burning position/thermal properties of a metal halide arc tube


https://www.lighting-gallery.net/gallery/displayimage.php?pos=-154383

https://www.lighting-gallery.net/gallery/displayimage.php?pos=-154318



please dont be so misleading to a new member like that who might not know better.




as for the OP, running the lamp for 10 minutes on a CCFL ballast, as RRK says thats fine, 10 minutes I doubt would of likely done it any harm


the ballast capacitor sounds good to me, 24uF is correct, have you double checked the voltage taps on the ballast? a lot of these US ballasts have multiple voltage taps, so I wonder if your perhaps accidentally have it on the 208V or 240V tap or such like?

for example doing a very quick ebay search I see while Venture have Orange as the 120V tap, for "Universal" branded ballasts Orange is 208V, so I would double check




also on the lamp front, have you tried operating it in different positions, or in the brief time it is working, to tap the bulb? does that cause it to go out or such? with this im trying to work if there is a bad contact thats acting like  a bimetallic switch as the lamp warms up

I just did some research, and as it turns out, this lamp in fact is a blue/UVA lamp. It is for developing certain types of photos I believe. They are meant to be operated on a normal m-59 CWA ballast, but with a slightly larger capacitor! I just tried it out to make sure and it worked perfectly and didn't cycle. I added a 5 uF motor run capacitor in parallel to the existing capacitor. From what I could find, the wavelength emitted by this lamp is not super harmful, but I am definitely not just going to use it for general illumination applications. From my research, the actual running wattage of this lamp is 500w, but only for short periods of time, just to develop a photo. Their lifespan is not super long either. I could only find 1 reference to this lamp on Lighting-Gallery, so it must be at least a little rare. Thank you so much RRK and Maxim, I wouldn't have figured this out without you.
 

Thanks!

I know what you mean, the car I have now is the only automatic I've ever had, so I do find myself looking for a non-existent clutch pedal sometimes..! I also occasionally reach for a gear lever, and as the car is LHD and I'm used to RHD, I bang my hand against the door 

@Rommie, to be honest, owning two cars is awesome! Especially when one is automatic, while the other is manual. It's weird switching from a manual back
to automatic, because you end up naturally searching for a clutch pedal that isn't there.
To my dismay though, both cars were down... so I had to use my motorcycle as my main source of transportation. Motorcycle riding is awesome, but when it's
your only source of transportation, it does take the fun out of it. Just a little.

@ suzukir122 - "down to just one car"... I've never known what it's like to have more than one, although I did have a car and a motorcycle together for a while, not the same thing, though.

This may be a little irrelevant but it further enforces on the problem where the best working lamp breaks while the eol/bad condition one is fine. When I was extracting two VFDs, the one with small pins and chipped glass survived but the best condition one with long pins lost vacuum (black spot=vacuum good & white spot=vacuum loss).

Yesterday,  I got a dream that I could take a 6500k F40T12 and hold another smaller tube of a different colour and squeeze them to 'merge' them (F40T12 with the smaller tubes colour).

Some 'Diazo' in the lamp name may point to UVA/blue special application lamp. Are sure this one is really rated 400W/M59?

On your photo some black sputtering can be noted, but it looks pretty minor. Really well-aged MH lamp often have burners looking completely black, but still start and run-up properly. AFAIK, tungsten electrodes in MH lamps are made from solid tungsten, often thoriated in the volume for activation. That kind of electrodes is very robust and hard to kill.