Sony HB-G900P
This page was last modified 13:48, 17 December 2021 by Mars2000you. Based on work by Rderooy and Msxholder and others.



The HB-G900P is the adaptation of the HB-F900 for the European market. This computer supports superimposition with genlock. The special video I/F connector on the back can be used to connect the Sony HBI-G900P Videotizer, which enables you to actually record the superimposed video and can also perform digitization. In addition a second internal disk drive could be added in the form of the HBD-G900.

It has a built in Video Utility ROM: Laser Disc control (using the RS-232C interface) and an MSX-BASIC extension to show large texts on the screen (useful with superimposing). Note that SonyLDP BASIC is not compatible with the Pioneer P-BASIC.

This model was a special computer aimed at the professional market. The keyboard is separate from the main unit. This model is only available in white color.

Comes with a single disk (please see the manual): MSX-DOS/Character Font System and Font Disk.

Included manuals: Operating Instructions, A Guide to MSX-BASIC version 2.0, MSX-BASIC Version 2.0 Programming Reference Manual, Reference Chart, Video Utility, A Guide to RS-232C Communication.

The HB-G900P was later replaced by the more advanced model HB-G900AP.

Brand Sony
Model HB-G900P
Year 1986
Region Europe
Launch price
RAM 64kB in slot 3
VRAM 128kB
Media MSX cartridges, 2DD floppy disks
Video Yamaha V9938
Audio PSG (AY-3-8910)
Chipset none (separate IC's)
Keyboard layout QWERTY wih a "£" key + numeric keypad
Extras One or two 720kB 3.5" floppy disk drives, superimposition capacity, reset button, RS-232C interface, software
Emulation ROMs dumped and emulated except for the superimpose and genlock functions, SonyLDP BASIC


Sony HB-G900P
HB-G900P with Videotizer
Sony HB-G900P back
Sony HB-G900P & Videotizer rear


The HB-G900P is a MSX2 with a Z80A from Sharp (LH0080A) and without MSX-Engine. Floppy Disk Controller chip is the CXD-1032Q (Sony).

The architecture is with standard components. The RAM is 64 kb in primary slot 3. The rs232 has an 2kb Sram for buffer and variables.(See service manual)

The optional AV creator HBI-900 interface has been replaced by the Videotizer (HBI-G900), a simplified interface to digitize images and do superimposing for the European market.

Slot Map

Slot 0-0 Slot 0-1 Slot 0-2 Slot 0-3 Slot 1 Slot 2 Slot 3
Page C000h~FFFFh Cartridge
Slot 1
Slot 2
Page 8000h~BFFFh
Page 4000h~7FFFh Main-ROM Disk-ROM RS-232 Firmware
Page 0000h~3FFFh Sub-ROM