Mercury Vapor n39 ballast light pole light burning out after one cycle on

I have a light pole. From a car lot or grocery store. I use it at the end of the driveway. it is a 120v. ie 1 power line. It has a ballast in the pole itself. I ran it for a couple of months with a switch to turn it on and off. Seemed to be no problem. I then wired in a photo sensor and it seem to work for a couple weeks. Then the bulb blew. Now when I put a bulb in(new)- It will ignite and go through one cycle but it blows @ end of cycle. whether the photo cell turns it off or if I turn the switch. Ideas?

It's not your hang on the wall security light.

 

I know the photo sensor is some what working because when I put a new bulb in and cover it during the daytime. It ignites and you can hear the ballast hum. There is no water getting to it. circuit breakers don't get tripped. I don't particularly want to start rewiring or taking out the photo cell. Plus the ballast is in the light pole. It does have a hing to lower it some. But I'm guessing the ballast is at least 10 or more years old. I have another light pole with same vintage ballast . I've put one 175w phillips and a sylvania HID bulb. Both have blown after the one ignition. Am I using the wrong bulb? If the ballast is bad or replacement is cheaper then trouble shooting and burning bulbs. Which
newer ballast should I rewire into pole and bulb?

 

The ballast is pretty much shot right there.

Just be aware that there will be no more new MV ( Mercury Vapour ) ballast in stock so the next type will work is Metal Halide ballast ( this one will come either probe start or pulse start )

Or go with screw in CFL and bypass everything { on ballast }

Merci,
Marc