Have a chandelier in our dining room that is about 40 years old. Some of
the lights don't work that well. One has to twist the bulb(s) to just the
right spot in the socket to get them to stay lit. Through vibration or for
some other reason some of them will shut off by themselves.

I can twist the bulb back in to make it work again to make it work.
However, I'm getting tired of that game. I was thinking of replacing the
whole unit as one can buy a new one for $100-$200. Or, is there a simple
and inexpensive way to repair these type of sockets?

http://www.shadesoflight.com/images/chandsolution.jpg