I have a discontinued hanging fixture over a table that has 3 halogen bulbs inside of MR16 sockets. I recently had the electrician change all 3 bulbs but one of the bulbs went out 2 days later. He came back, investigated, and said the MR16 socket was burned out and he'd replace it. He tried to use what he called the standard MR16 socket, but realized he couldn't since the original socket had special housing built in to hold the socket and breaker for glass and the standard MR16 socket's holes didn't line up with the holes in the fixture. The electrician said that most likely the company that manufactured the fixture had the sockets specially made. We called the manufacturer and they no longer make any fixtures calling for MR16's, and had none they could sell me either.
Any ideas on how to fix this would be greatly appreciated! I love the fixture and would really like to keep it.
Thanks so much.

Need to have the electrician find three lampholders that fit in the fixture for a suitable lamp.

If you would review this:

Halogen Repair Parts

You will see that there are many types of lampholders available, and these are not the only ones.

Someone will need to take the time to research to find the one that will fit.

There may be an appliance or lamp repair shop in your area, that could help.

Thank you so much for your quick reply. I looked at the page with the halogen repair parts and the only one that looks like what is in my fixture is the A211107 but the holes in my fixture are 1" apart and those on the A211107 are only 7/8" apart assuming I read the description correctly. The A211107 looks like what the electrician tried to use and which I thought was called an MR16 socket. Am I understanding you then, that as long as the holes line up, even if the shape is different, as long as it fits inside the fixture, it could work then?

Yes.