Dumping/reverse engineering MSX models thread

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By Patrick

Supporter (14)

Patrick's picture

07-05-2020, 17:39

Patrick wrote:

I will do this in the next.

...days.
So, it's done.
IDENT result is here (from silkscreen it is a 9129/28/18 and there is 2 TMS4416 as VRAM).
MSXMEM result is here (BIOS and Basic, slot 0, 64ko RAM slot 1, disk ROM slot 2, nothing in slot 3).
If you need something else, let me know.

By Manuel

Ascended (18136)

Manuel's picture

07-05-2020, 21:26

Thanks, Patrick, that helps.

Yes, you can do more:
1. Run SWIOSCAN.BAS
2. Run KEYMATRIX.BAS:
This utility shows a 1 for each key not being pressed, and a 0 for each key
being pressed. The first thing is to take a picture of the screen while
pressing the following combination on the keyboard:

SHIFT+GRAPH+0
2.b. Check if there is a CODE key with a LED and whether you can toggle the LED with that CODE key. Same for the CODE key, although that one doesn't have a LED, but please check whether it has toggling behaviour for the character output when typing after pressing and releasing it repeatedly.
3. Make a picture of the keyboard (so we can see whether there are special keys and such)
4. Make a picture of the main board, showing the chips so we can read what's on them
5. Make a picture of the back, showing the type plate

Thanks a lot! Smile

The machine seems to be based on the Daewoo DPC-200, but it has a different slot layout! Quite amazing. For what reason??

By Manuel

Ascended (18136)

Manuel's picture

12-05-2020, 16:53

Any news Patrick?

By Patrick

Supporter (14)

Patrick's picture

12-05-2020, 17:54

Manuel,
I have done the other tests as well but these are less interesting.
1. Result is No IDs if I remember correctly, so no screenshot.
2. As for SHIFT+GRAPH+0 press, the result is here.
2b. May be you mean CAPS? Yes, CAPS has LED and toggles on press. No LED for CODE key. No toggling.
3, 4 and 5. There is already good pictures in the wiki. My PHC-2 is not different (may be less yellowed).

By Manuel

Ascended (18136)

Manuel's picture

12-05-2020, 19:51

Patrick: regarding 4 and 5, I'd like to see the pics of YOUR specific machine. Perhaps it's a different revision and perhaps we can see the chip names on your machine. And the type plate with serial number is there for reference, so I can document on which machine the openMSX config was based.

Looks like this keyboard has SHIFT-GRAPH protection Smile Thanks for testing.

By Patrick

Supporter (14)

Patrick's picture

13-05-2020, 18:29

Manuel,
3. Photograph of the keyboard is here.
4. Photograph of the main board is here.
5. Photograph of the plate is here.

By Manuel

Ascended (18136)

Manuel's picture

13-05-2020, 21:34

Thanks a lot! Too bad the VDP type isn't visible. I recon it's a TMS9129, based on your ident.bas tests.

By Manuel

Ascended (18136)

Manuel's picture

13-05-2020, 21:51

Manuel wrote:
dproldan wrote:

Got it, thanks! I dumped the ROMS as 64KB files and put them here: https://drive.google.com/drive/folders/1_4Tvv1YcH99fyE8MnQuZrTJE3MhYicwI?usp=sharing

Thanks! Which of these dumps are from which slot?

dproldan?

By sdsnatcher73

Prophet (2232)

sdsnatcher73's picture

14-05-2020, 06:13

Manuel wrote:
Manuel wrote:
dproldan wrote:

Got it, thanks! I dumped the ROMS as 64KB files and put them here: https://drive.google.com/drive/folders/1_4Tvv1YcH99fyE8MnQuZrTJE3MhYicwI?usp=sharing

Thanks! Which of these dumps are from which slot?

dproldan?

The dumps are from the (EP)ROMS of the board (his computer is not booting). So we can’t identify the slot layout from these. But I am quite sure the mainboard for the YIS805/128R2 is the same as the YIS805/128 and YIS805/256. The image of the board for YIS805/128R2 has some clues to that effect:

1. On the rear you can see the connector marked CN313 which is for the expansion bus available only on the YIS805/128 and YIS805/256. It is 50pins so likely MSX slot layout and a Toshiba HX-10 style flat cable connector.
2. On the left you can see the memory with 256kB written on the board and 4 out of 8 places populated with chips (indication that this board is likely to have been used for YIS805/256 as well.
3. There is a round cutout to the left of CN313 and a large CN311 (60 pin Yamaha style) in the middle of the YIS805/128R2 which imho were used for the RS232 board and external connector for the YIS805/256.

Also the dumped ROMs of the YIS805/128 from dpoldran correspond to the ROMs of the YIS805/128, the EPROMS are 64kB and only 32kB was actually used but they were easy to identify when compared to R2 ROMs.

Of course these are guesses and speculations but there clues are there and from other models we know Yamaha was reusing rather than redesigning boards. Of coarse an image of the mainboard of dpoldran’s machine would be a quick confirmation.

YIS805/128R2 mainboard:

YIS805/128R2 back case (no external access to extension bus CN313):

YIS805/128 back case (with external access to extension bus CN313):

By Manuel

Ascended (18136)

Manuel's picture

14-05-2020, 08:38

It still doesn't tell everything. E.g. the Olympia PHC-2, clearly based on the Daewoo DPC-200, has a different slot layout than the DPC-200.

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