Gradiente Expert Plus
This page was last modified 16:12, 3 November 2021 by Mars2000you. Based on work by Rderooy and Gdx and others.




The Expert Plus was the third MSX1 computer released by Gradiente. Compared to Expert GPC-1, a reset button has been added, RGB and bus expansion connectors have been removed. Main RAM changed from slot 2 to expanded slot 3.0.

Brand Gradiente
Model Expert Plus
Year 1989
Region Brazil
Launch price
RAM 64kB in slot 3-0
Media MSX cartridges
Video Toshiba T6950, Texas Instruments TMS9918 compatible (Integrated in MSX-Engine T7937A)
Audio Toshiba T7766A, General Instrument AY-3-8910 compatible (Integrated in MSX-Engine T7937A)
Chipset Toshiba T7937A
Keyboard layout QWERTY with a "ç" key + numeric keypad
Extras built-in speaker with volume control, reset button, firmware: demo called "Ligue-se ao Expert"
Emulation ROMs dumped and emulated


This computer comes with a built-in firmware that is a modified version of the demo cartridge provided with the Expert XP-800 and the Expert GPC-1 machines.

It starts with a menu including two options (MSX-BASIC and Applications). The Applications submenu has 5 options (Drawing, Music, Consumption, Receipts, Back to BASIC).


Gradient Expert Plus
Gradient Expert Plus - back
Gradient Expert Plus with manual
Gradient Expert Plus PCB
Gradient Expert Plus - box


The Gradiente Expert Plus is a MSX1. The Z80A, the VDP and the PSG are integrated in MSX-Engine T7937A.

The integrated VDP is the Toshiba T6950, which does not support some undocumented features of the Texas Instruments TMS9918, TMS9928 and TMS9929 VDP's.

The RAM is in slot 3-0, what has been source of trouble for some programs written for the two first Gradiente computers.

Slot Map

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