Who repair vintage turntables?

I have a Dual CS5000 that suits my needs, but the tonearm may need to be restrung, I'm picking up a little hum that I don't seem to remember being there.

Also, a friend of mine has an old 1228 that has never seen service. All his records are in mint condition, and he doesn't trust it any more, but he would like to see if it could be revived.

We have both gone though the process of evaluating suitable replacements, however the cost is something neither of us can justify, but if we recondition own now, it would service our needs.

This would have to be a professional service, someone who does this for a living, and can warranty their work.

Any suggestions?