Do any of our readers know why a hole is at the lower edge of the
sound board in my 1923 Weber Duo-Art Upright Electric Piano?

Should I close it or just let it remain?  What is its purpose?

The pump in this unit is the large steam boat pump.

Grahame Code
Australia

 [ The hole is provided for an electric cable, which may be mains
 [ power for the system or else an external power switch, etc.
 [ I think it's safe to leave the hole as is.  ;-)  -- Robbie