Tecnobytes V9990 Powergraph
This page was last modified 16:57, 8 December 2021 by Mars2000you. Based on work by Gdx and Tvalenca and others.



The Tecnobytes V9990 Powergraph is a cartridge based on the Sunrise GFX9000, and can be used with any MSX computer generations. It is built around the Yamaha V9990 Video Display Processor. The V9990 is based on the never released Yamaha V9978 VDP, which was supposed to be used in the MSX3.

Compared to the Sunrise GFX9000, the V9990 Powergraph has the same specifications with the addition of NTSC composite video and S-VIDEO outputs. The RGB connector uses a DE-15 subminiature connector instead.

Its first and second revisions were sold for $125, both now discontinued in favor of a "light" revision with $89 price tag (a very welcomed price drop). Please refer to Tecnobytes' website for availability and current price


Tecnobytes V9990 PowerGraph cartridge
Tecnobytes V9990 PowerGraph PCB
Tecnobytes V9990 PowerGraph Light with its S-Video adapter
Tecnobytes V9990 PowerGraph Light PCB


The V9990 Powergraph allows all Yamaha V9990 video capabilities to be used on MSX, and contains 512kB DPDRAM (dual ported dynamic RAM) memory.

Unlike the GFX9000, which used either Toshiba's or Mitsubishi's 128kB DPDRAMs, the V9990 Powergraph uses Samsung's 256kB DPDRAMs.

The video encoder IC used is the Sony CXA2075 (instead of Sony's V7040 used on the GFX9000). The video signal generated by the V9990 is available on all of its output connectors simultaneously (only on V1 and V2, Light version dropped the extra connectors in favor of a breakout connector).

Just like the GFX9000 it still requires a second monitor for proper usage: one monitor connected to the MSX, and the other to the V9990 where video will only be shown when a V9990 enabled application is running.

Please check the Yamaha V9990 page for detailed information on its graphic capabilities.


The V9990 Powergraph is meant to be 100% compatible with the GFX9000, so any software written for it will work.


  • RGB out (via DE-15 connector)
  • CVBS out
  • S-Video out

On Powergraph v1 and v2 CVBS and S-Video outs are immediately available, but on Powergraph Light those connectors are only available through a supplied breakout board.

Pinout of the DE-15 connector

PowerGraph v1 and v2

The 1st and 2nd versions of the PowerGraph features a DE-15 subminiature connector with a custom pinout. 1st version uses a male connector, while 2nd version uses a female connector, but the pinout is the same.

Pin Signal
1 R_out
2 G_out
3 B_out
4 V_sync_in
5 Csync_out
6 YS_out
7 DLCK_out
8 3.58MHZ_out
9 H_sync_in
10 Croma_out
11 Y_out
12 GND
13 H_sync_out
14 GND
15 GND

Powergraph Light

Powergraph Light uses a different pinout, meant to carry the signals needed by the breakout board for CVBS and S-Video connectors. The connector used is a DE-15 subminiature like V2's.

Pin Signal
1 R out
2 G out
3 B out
4 S-Video C
9 +5VDC
10 GND
11 Not Connected
12 S-Video Y
13 H_Sync
14 Not Connected
15 Composite Video


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