Autoharps

These are examples of various Autoharps

Oscar Schmidt Centurion autoharp (OS-100-21) Oscar Schmidt “Centurion” autoharp (OS-100-21) US made with magnetic pickup, set up as a chromatic instrument; a suggested 21-chord bar arrangement is shown below.

Treble side

Co7       F7        C7        G7       D7       A7       E7
    C#o7      F          C         G         D         A         B7
        Do7       Dm       Am       Em      Bm      F#m     F#7

Bass side

Here Co7, C#o7, and Do7 are diminished seventh chords.
OS15B Converted Oscar Schmidt OS15EBH US made between 1969 and 1972 converted with luthier cord bars  and fine tuner (Schreiber Autoharps).  

Treble side

Bb       C7        G7       D7       A7       E7
     F          C         G          D         A           E
       Dm       Am     Em      Bm      F#m    B7

Bass side

Grand Parlor Autoharp 1895 Parlor Grand Autoharp from Eileen Roys’ Autoharp Museum
Chromaharp Caroler ChromAharp Caroler…this instrument (in Eileen Roys’ Autoharp Museum) was designed to be played lap-style by right-handed players, apparently because of its size and weight; it has 27 chord bars and 43 strings.  The chord bars are quite narrow and do not do a good job of damping strings:
Solid Body Electric Solid-body electric Oscar Schmidt autoharp