One thing to note is that the "Fill In" button on the left seems to be stuck down. Study photos carefully.
Vintage Yamaha Portasound PSS-31 Electronic Keyboard Synthesizer Tested Working
Vintage Yamaha Portasound PSS-160 synth keyboard With Box and books
Vintage Yamaha PortaSound PSS-170 Electronic Keyboard With Case BOXED WORKING
Vintage Yamaha Portasound PSS-50 Electronic Music Keyboard Boxed Tested Working
Vintage Yamaha Portasound PSS-9 Electronic Keyboard Black Voice Bank 32-Keys
Vintage Yamaha Portasound PSS-50 Electronic Music Keyboard Boxed Buzzing When On
