Switch between MSX2 mode and MSX 2+ mode

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By edoz

Prophet (2363)

edoz's picture

08-05-2011, 23:29

I have a MSX 8280 that is upgraded somewhere in the ninetees ..
Also Somewhere in time i changed the front of the MSX. (Because it was newer and had a better look) on the old front it was possible to switch to MSX 2 mode or MSX 2+ mode. Also it was possible to enable 7 Mhz or not. For some reason i don't now why i never created this switches on the new front of the MSX. But i like to do it now.
I'm not a hardware specialist .. but i need to know where i need a switch to swap between MSX 2 or MSX 2+ .. is this possible ?
Does someone know where to connect the wires in the mainbord. Is it also possible to enable or disable FMPAC.
I know already where to find the pins for switching between 3 Mhz and 7 Mhz..

See Images from the MSX8280 mainboard. If you need more pictures from a special location let me know.

Thanks so far.

members.home.nl/evanzanten/MSX8280.JPG

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By Meits

Scribe (6434)

Meits's picture

09-05-2011, 06:37

It is possible, so I was told when my MSX got 2+'ed. But the question 'Why would you want that' was asked in the same breath.

By Daemos

Paragon (1951)

Daemos's picture

09-05-2011, 09:39

Question about the photo: Why did someone scratch the numbers of the IC's and especially only the serial and production number of the FM chip?

By Huey

Prophet (2675)

Huey's picture

09-05-2011, 09:45

Question about the photo: Why did someone scratch the numbers of the IC's and especially only the serial and production number of the FM chip?

IIRC it was standard procedure for MSX club Gouda. Afraid someone would copy the design and they would make less money.

By Repair-Bas

Paragon (1115)

Repair-Bas's picture

09-05-2011, 10:41

It is 100% sure that this computer was modified by msx-club gouda.

It is not possible anymore to switch to msx2, because there are only msx2+ rom in this computer

By Huey

Prophet (2675)

Huey's picture

09-05-2011, 11:02

It is 100% sure that this computer was modified by msx-club gouda.

You're right. I cannot know for sure. Hannibal

By Daemos

Paragon (1951)

Daemos's picture

09-05-2011, 12:04

It is not possible anymore to switch to msx2, because there are only msx2+ rom in this computer

Is it not possible to design a cartridge that does this, holding the ROMS etc?

By luppie

Paladin (862)

luppie's picture

10-05-2011, 00:38

I would love to have the design of the FM-Pac PCB, still have some spare YM2413's to build in some MSX's
The 8 pin IC must be a simple OPAMP, so could'nt be to hard to rebuild it.

By edoz

Prophet (2363)

edoz's picture

10-05-2011, 08:27

Repair-bas ,are you sure there are no MSX 2 roms anymore ? because the 3 big ones (i'm not a hardware guru) are 6 .. You cannot see this on the picture because the picture is taken from above. There a 3x2 roms overthere.

Luppie, I have no design of the FM-Pac but if you want i can make more pictures ?

By edoz

Prophet (2363)

edoz's picture

10-05-2011, 08:37

members.home.nl/evanzanten/MSX8280-2.JPG

By NYYRIKKI

Enlighted (5838)

NYYRIKKI's picture

10-05-2011, 10:27

Indeed it seems that the ROM's can be changed. This is controlled by the 2x2 gray wires connected abowe texts IC119 and IC118. How ever from the picture it does not come clear to me where those wires go or how the logic works after that.

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