The PortaSound PS-400 was released at the same time as the Yamaha PS-300 and is the higher-end model of the pair.
Year Released: 1982
Keyboard: 44 keys
ROM: 10 sounds, 10 rhythms
Power Consumption: 2.3 watts
Dimensions: 621 mm x 152 mm x 43 mm
Weight: 1.6 kg
This keyboard has built-in 1.4-watt mono speaker(s).
Batteries: C x 6
Yamaha PSREW400 76-Key Portable Keyboard ($466.08)
Yamaha PSR-EW400 Keyboard ($418.60)
Yamaha PSR-EW400 ($473.99)