Short story long, we have acquired a beautiful zither, which, according to a tiny white-haired lady, was last played by her grandfather, who died in 1953.
Wild guess: The strings all need replacing.
So, who sells strings for what is apparently a "Concert zither"?
Fingerboard with 5 strings, and then 29 more strings.

Would a set of Oscar Schmidt autoharp strings work?

Possible sources would include Anne Prinz (ATOZTHATISME@AOL) and Schneidermusic.de.

Rudi Mueller, Grafton, Ozaukee County Wisconsin
RMUELLERMKE@GMAIL,COM

I stopped today to talk to the "tiny white haired lady", who still works at Heim's shoe store and leather repair shop in Grafton WI, and fondly remembers her grandfather playing the zither. Her grandfather was Joseph Schauble of Port Washington WI, where he was employed at the chair factory. In addition to zither, he played clarinet in the Port Washington civic band.

rudi