Gradiente Expert XP-800
This page was last modified 16:13, 3 November 2021 by Mars2000you. Based on work by Rderooy and Gdx and others.




The Expert XP-800 is a computer that looks like the National CF-3000 and was released by Gradiente. This model was presented to the public at the 5th International Computing Fair, nicknamed "Informatica '85".

The event took place at Anhembi Exibition Center in the city of São Paulo from September 23th to 29th, 1985.

At the announcement, the computer was priced 65 ORTNs.

Released in 1st december 1985, it was the second MSX home computer to hit the Brazilian market, just a week after Sharp's Hotbit. Just in time for Christmas and with a massive media campaign on magazines, newspapers and TV. But in the newspapers ads the offer price was Cr$ 4.640.000,00 Brazilian Cruzeiros (BRB), or US$ 493,62 (USD) by the value at the time.

The detached keyboard with numeric keypad granted a "professional" look. Because of this, the Expert was the MSX model most featured in Brazilian TV, like soap operas and humouristic shows.

In addition to the cardboard box and the polystyrene, the units were shipped with two manuals, a quick reference guide, demo cartridge, TA-1 switched TV adapter, video cable, cassette cable, 0.5A fuse for 240V, covers for the joystick ports, and 15 adhesive labels for the function keys.

The color CRT monitor shown at the box print and manual covers was a mockup.

Contrary to popular belief, this wasn't just a rebranded National CF-3000, but an unauthorized copy. The case was bigger, and both main and analog boards layout were redraw. It didn't had support to an superimposition accessory, and had some of it's connectors changed to a non-MSX standard connectors (printer, cassette, RGB and keyboard). This also means that the connectors were on different places when compared to the CF-3000 model.

The Expert XP-800 was followed by the Expert GPC-1.

Brand Gradiente
Model Expert XP-800
Year 1985-12
Region Brazil
Launch price Cr$ 4.640.000,00
RAM 64kB in slot 2
Media MSX cartridges
Video Texas Instruments TMS9128NL
Audio PSG
Chipset none (separate IC's)
Keyboard layout QWERTY with "ç" and accents keys + numeric keypad
Extras built-in speaker with volume control, RGB output, easter egg in Main-ROM 1.0, demo cartridge called "Ligue-se ao Expert"
Emulation ROM dumped and emulated. The shared 2nd cartridge slot with the rear expansion port is handled like a single MSX cartridge slots.

Easter egg

The ROM version 1.0 has an easter egg. The Gradiente staff's names are displayed on screen after the execution of these commands in direct mode: DEFUSR=5032:A=USR(0)



Gradiente Expert XP-800
CF-3000 and XP-800 in comparison
Gradiente Expert XP-800 back panel. Marked CONSOLE MOD. C-1
Gradiente Expert XP-800 - box
Gradiente Expert XP-800 - manuals
Demo cartridge (2 units shown)
Gradiente Expert XP-800 - extras
Detail of Gradiente Logo on plugs

Easter egg

Gradiente Expert XP-800 easter egg (ROM 1.0)


The Expert XP-800 is a rather complete MSX1, with full 64KB of RAM in slot 2. It has a Z80A from Zilog.

Slot Map

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


Note: No RF output (the TA-1 TV adapter is required)


Good/strong features

  • It has a internal speaker with a good audio amplifier. If the volume control is set at the maximum level, the sound intensity can be annoying.
  • A DIN-8 RGB video output is provided.
  • Two switched electrical AC sockets are provided.
  • It has a 50-pin bus expansion port, which shares the slot 3 selection, in such way that if a cartridge is inserted at the "Cartridge B" bay, the /SLTSL signal for the rear connector is disabled.
  • Just as in almost every Brazilian electronic appliance, the power supply has a selector switch for 120/240 VAC, this way the unit can be used in places with mains of 220~240VAC.
  • It has a monochrome video output, which provides a clear luminance signal that looks best than composite in monochrome monitors.

Bad/weak features

  • The RGB output pinout is non-MSX standard, and *WARNING* one of the pins is a +12VDC.
  • The cassete interface is a DIN5 socket, non-MSX standard.
  • The printer port is an IDC-26 socket, non-MSX standard.
  • The external TA-1 module is needed to convert RGB to PAL-M Composite Video, or to RF in channels 3-4 VHF.
  • It lacks a RESET switch and a CAPS LOCK LED.
  • The BUSDIR signal is a TTL Tri-state output, non MSX-standard.
  • The first batches came with bad quality sockets for all ICs in the digital PCB. After some hours of use, thermal expansion caused crashes that required the computer to be opened, in order to re-tight all ICs back in their sockets.
  • The Portuguese accented letters must be typed as graphical characters, sometimes by pressing a combination of 2 or 3 keys together, not in the same way they would be typed as in a typewriter machine.
  • The position and the proximity of the two slots poses an issue if you want to use big cartridges like NMS-1205 Philips Music Module, or Panasonic FS-CA1/FS-UV1.
  • Soon the painted letters of the keyboard started to wear-off and vanish, mostly in the cursor keys.
  • The keyboard can't be positioned close the console if a joystick is connected.

Some different things

  • The numeric pad disposition on the PPI keyboard matrix is non-MSX standard
  • LGRA/RGRA labeling for the MSX GRAPH/CODE keys
  • Black background & border SCREEN 0 default, instead of the standard dark blue SCREEN 1

Clearly, this was the result of Gradiente never being an officially licensed MSX maker, thus they didn't had the oficial documentation at their hands and lacked the knowledge on what was standardized.

Accented Character Issues

Gradiente Expert XP-800 keyboard

A small difference in the ASCII table between both 1.0 ROM versions of Expert and Hotbit caused accented character issues for users in Brazil. Algo creating trouble for software developers and printer manufacturers. This can be fixed replacing Main-ROM by the ROM from Expert GPC-1.

Due to this issue, most of Experts XP-800 (and Hotbit as well) undergone a recall to replace their original 1.0 ROMs by the 1.1 version, and also to change 9 keys of their keyboards. Nevertheless, brazilian MSX users often call this machine "Expert 1.0" despite the upgrade of ROM to version 1.1