Casio Casiotone MT-65, 1983, made in Japan

RCA output, headphone jack, 20 sounds, 12 beats, accompaniment, 2 forms of sustain, and built-in reverb. The drum machine has a fantastic sound to it. The key sounds are wonderful and can be easy modified with a variety of settings, including the arpeggiator, the waveform modulation, and you can add effects like vibrato, sustain, and reverb. 

Link: Owner's Manual PDF Service Manual & Part's List

Specifications
Year Released: 1983
Keyboard: 49 keys
Polyphony: 8 notes
ROM: 20 sounds, 12 rhythms
Effects: vibrato, sustain, reverb
Power Consumption: 2 watts
Dimensions: 633 mm x 188 mm x 71 mm
Weight: 2.6 kg
This keyboard has built-in 1-watt mono speaker(s).
Batteries: 5 x D