This is a reverse engineered schematic of the Toshiba HX-51 MSX1 computer, PAL version.
It is derived from an original that I'm fixing. The PCB was single layer with a lot of wire jumpers to bring signals in the proper section.
The machine is built around a Toshiba T7937 MSX Engine (CPU, control, VDP, Audio, I/O) in a TQFP 144pin. I derived most of the pin function by an old file in portuguese, but some pins are adjusted on what I discovered in the machine and renamed some other.
It's still not clear the function of some of the selection pins (with external jumpers with no description), and two are marked as ??? because I don't know the function of them.
If anyone has any further information about that IC, please let me know and I will correct the drawing accordingly.

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