Well, since I work second shift and the wife works third, I often take bike rides down the mile and a half long road outback of my house at night, usually after midnight. just tonight I took a ride at about 3 AM and it was very foggy out and kind of chilly about 60° when suddenly I noticed that the last yard blaster style clear mercury vapor light which was the only light on the road, I am thinking there used to be more but they were removed… It was a clear mercury vapor lamp with a ballast that hummed, it was halfway down the one-mile stretch and was a nice marking point has since it's like actually illuminated quite a large area of the road. it was a bluish green dimmer one, very very old looking. It was out tonight :-( I have come to really like that lamp as I will stop underneath it for a break when I am biking. There is a house slightly on the road, but this is pretty much backroad. I'm not really sure we're gets power from. but it is definitely ancient fixture! I wish there was someway I could put a new bulb in lt, I wonder if that is what is wrong? I have seen other ones died across the street and they never replaced or fixed them. if there is someway that I could do it at nighttime I probably could get away with it because no cars travel this road, but I figure it would be dangerous. I doubt the township would care enough if they're letting all the other ones go to replace this. There are newer cobra head sodium lamps that are closer to the house but this was on the back road and I really liked it :-/ the fixture is very corroded, it droops slightly, and reflector was very yellowed. The bulb was not blown tubular but the other style that I like best with the little dimple at the top, clear, and very greenish with a buzzing ballast :-( darnit!! I just don't know if there are any type of contraptions with a long rod that I could actually reach out and unscrew the bulb and put the new one, I could probably pull it off especially if I road a bike out to the area but whether it would be worth it or not, it may be too too dangerous.

I would rather guess the ballast died. As you said the fixture was corroded, so I would guess it was not anymore waterproof, so the ballast could corrode as well and die as the result...

That makes sense man, actually the night before we had a pretty good rainstorm, and quite a steady downpour the entire night, something we haven't had for quite some time! It's a shame, it will probably hang there nonfunctional for many years :-/. I wonder if I could use some contraption to pluck the old blue green bulb lol! Oh well.

Maybe one of those commercial lamp changer poles would reach it? Some of those are 15+ feet tall plus your height, so over 20 feet reach (even higher with a ladder). As long as the lamp isn't seized in the socket, it should work, though it may need some jiggling to get the bulb to start to turn. It is nice to see an old  lighting a yard or back road. The bluish moonlight color is so much easier on the eyes than  .

I love the blue green color of  too!!

They actually make a version of those bulb changer poles designed for ED28 HID lamps. Not sure if they work as well

Oh and I wouldn't so easily discount the fixture as having a dead ballast, the older ones were quite bulletproof and I've seen ones with rusted out ballasts still fire up perfectly albeit with a slight buzz though.

The rust itself does not prevent the ballast from working (it's magnetic properties are about the same as iron, moreover it is not conductive, so the eddy current losses could be lower), but it is it's mechanical expansion (compare to clean magnetic steel), what usually overstress the winding from inside so, the wire insulation crack and cause interturn shorts. So if the coil is more loose on the core, it mean way higher chance, the ballast could survive way more severe rusting, than if the coil is tight around the core.
But the loose coil does not mean more reliable ballast in general: It usually mean the wire is thinner than it could be, so the wire resistance losses would be higher on such ballast than the tightly assembled equivalent of the same size, so it would operate hotter, what mean shorter lifetime from other effects.
And even when the ballast heavily rusted outside, the main core inside the coil could be still clean, so not stressing the coil, while another ballast could be only lightly rusted, but even inside the coils, so they get damaged...

I was talking about actual examples I've seen both in real life and on this site....

Who know, what happened there. The light was in daily use, what usually quite well protect it from rusting, as the generated heat dry it out completely. The water can not seep deep into the core during so short time the ballast is cold and the air humid to condensation, so if it rusted, it would be only on the surface. Unless the water was really dripping on the ballast or if it was immersed in a "pool" there. But the shape of housing components used for old fixtures was usually so, it make at least an effective roof, so the sealing was there only to keep bugs and dust out...


The problems with rust expanding cores damaging the winding I've seen mainly with transformers, what were not in use for quite a long time and I think two fluorescent ballasts.

Yardblaster type fixtures usually have the ballast more or less suspended inside, water can't accumulate there...

Also I really don't like having to defend my point on here...