There are several new and used "Mechanik für Zither" (search word) currently listed on e-bay.de. Asking prices are in the range 20-25 eu.

Rudi

I had good success sending two of mine to Jeffrey at Rubner in Markneukirchen for repairs. I went to visit him a few years ago; he's not far from Meinel and from Wünsche Zither builders. If you're able to someday, it's a great quest to visit all three plus the city's music museum.