If they need restrung there are extra set still available but they are expensive, about 60 dollars a set. Fortunately the strings last a long time because they are not fingered so even if you buy a USA made one from the 70's the strings are likely to be OK.
"Chromatic" Autoharps have up to 21 chords (extruded aluminum chord bars can be made very thin, so more can be crammed on to the top of the instrument), and can play in most common "folk" keys.
The best ones and the ones people look for are the made in USA ones.
About 1983 they switched to Korea and sometime in the 90's China.
For an instrument probably selling for 0 or less, 0 worth of repairs may not be cost-effective (not that I haven't done it for an older instrument I wanted to play).
Haveta leave ya with my favorite Autoharp vid, Kilby Snow on his Sears Silvertone Schmidt model, with customized chord bars so he can get those slurs or "drag notes," played left-handed -- pure self-taught Appalachian playing: Allen Hopkins Gibsn: '54 F5 3pt F2 A-N Custm K1 m'cello Natl Triolian Dobro mando Victoria b-back Merrill alumnm b-back H-O mandolinetto Stradolin Vega banjolin Sobell'dola Washburn b-back'dola Eastmn: 615'dola 805 m'cello Flatiron 3K OM Overall, I'd start with something like the Model OS73C "1930's reissue," which is less than 0, discounted, for a 21-chord model and specs as having a solid spruce top. It is common even for those who do not purchase extra bars to change the order to place more commonly used chords closer together.