Yamaha YIS-503

The Yamaha YIS-503 was an MSX1 computer designed as a flexible base for education, graphics and music modules. Its side expansion slot accepted Yamaha’s specialised FM synthesis hardware.

The machine formed the technical foundation of Yamaha’s better-known CX music-computer family.

Notable Features

• Dedicated side module slot
• MSX1 compatibility
• Designed for Yamaha music and graphics expansion

Historical Significance

• The machine formed the technical foundation of Yamaha’s better-known CX music-computer family.

Collector’s Notes

• Regional versions and optional modules alter the machine’s capabilities; document installed cartridges and power supply.
• Memory, storage, displays and expansion hardware should be documented because configurations often changed during a system’s working life.

Specifications

Technical Information
Name	Yamaha YIS-503
Manufacturer	Yamaha
Launched	Saturday, January 1, 1983
Country	Japan
CPU	Sharp LH0080A / Z80A compatible
Units Sold
Form Factor	Keyboard console
Power	Internal or external mains supply
Networking	None built in
Operating System	MSX BASIC; MSX-DOS on disk-equipped models
Expansion / I/O	Cartridge, cassette, joystick, printer and video connections
Keyboard	Integrated keyboard
Storage	Cartridge and cassette; optional disk
Sound	AY-3-8910-compatible three-voice PSG plus noise
Colours	16 on MSX1; expanded palette on MSX2/2+
Graphics	TMS9918-family 256 x 192 pixel graphics
Display	Television or monitor
ROM	MSX BIOS and BASIC plus model firmware
RAM	32 KB main RAM and 16 KB video RAM
CPU Speed	3.58 MHz