Black stain ran around socket

[letterman]

I have one of those Mercury Vapor yard lights. Normally when the bulb burns out it starts getting dim and tends to go one and off. This time it just stopped working. I went up and replaced the bulb and noticed the socket had some black staining on it. The fixture should not be leaking water. Of course anything is possible. I am considering that dust and stuff combined with moisture could cause this too, however I do not recall seeing this in the past.

With the new bulb, it still does not work. This makes me wonder if it's the sensor or could the ballast have gone bad and that's the black stain? I realize no one can answer this for sure, but has anyone ever seen a ballast die, and does it leave a stain on the socket? I suppose I got to take the whole fixture down, and working on poles is not my idea of fun....

Thanks

[RBM]

once you open the fixture and expose the innards, you may find where the black stuff came from. Sometimes the igniter blows, and not the ballast . Depending upon the fixture you may be able to get replacement parts

[Don Young]

The control sensor is a common source of problems. On many lights it plugs into a twist-lock socket on the top of the fixture. Turn it counterclockwise (looking down on the top) a little, then wiggle it as you pull up. Replacements are usually available anywhere they sell the lamps.

Be aware that you can cover the sensor with a dark heavy cloth to turn it on, but it may take a minute or so for it come on as there is a built-in time delay.

Be careful!!

Don Young