Problem with direcional on games.

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By hardheavy

Resident (52)

hardheavy's picture

18-04-2011, 15:53

Hi everybody!. I´m from Brazil, then sorry for my poor english. Who can help me? I´ll be grateful.
One month ago i bought a MSX DD PLUS Gradiente, made in Brazil.
This msx model has a biult in 3 1/2 floppy disk, so the two fornt slots are free, and there is a internarl interface that connects the floppy and goes to a pin conector to a main board.

Games like Goonies , Zacac, Kings Valley , Knight Mare, loads ok , but the charaters always go to the top of the screen , even i never touch the keys of the keyboard.
So i decide do a test: i opened yhe msx and take off the joystick board from mainboard. So the charatecs stop go to te top of the screen by themselves, but i can olny control them to the right and left.
Trying to save de problem, i bought a new joystick board and connected on the mainboard. The problem remaim.

So i did other test: I have a disk verson of Nemesis I , verison 64 K, that doesnt need Megaram and this version boot automatically, just put the disquette on the drive and turn the MSX on. This version uses the full disk capability(720 K).
After load the game, Vic Viper goes automatically to the top of the screen, and if i press the DOWN direcional Key of the keyboard, it stops going to the top, but if release the DOWN key, the aircaft goes to the top.

On Basic screen and som games the direcional kys works normally.


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By Jipe

Paragon (1552)

Jipe's picture

18-04-2011, 17:12

test your MSX with a real cartridge game because this version is not "by Konami"

By flyguille

Prophet (3028)

flyguille's picture

18-04-2011, 19:44

you have stucked the UP key, or the joystick interface is broken

By hardheavy

Resident (52)

hardheavy's picture

18-04-2011, 20:40

I´ll try do do this. Thank you!


I put a new interface and the problem remaiins. In Basic mode the key is okay!

By hardheavy

Resident (52)

hardheavy's picture

18-04-2011, 21:19

I´v bought a new joystick controler board and the problem persists, even if i start the game(Nemesis 1 on disk) without keyboard.

By fukenko

Champion (357)

fukenko's picture

19-04-2011, 00:25

There might be a problem of joystick detection.
Please test following program without joystick.


If mainboard is right,"0" should be displayed.

By hardheavy

Resident (52)

hardheavy's picture

19-04-2011, 04:18

fukenko, thank you so much for the tip!.
i did what you said, then i digited RUN.

Appeared the number "1" .

So the mainboard has a problem?


Enlighted (5939)

NYYRIKKI's picture

19-04-2011, 06:21

I'm pretty sure there is failed LS157 (or similar) somewhere near PSG or Joystick ports. Problem should be easy to fix by adding few jump wires or by replacing the failed chip. Does anyone have a circuit diagram for this model?

By hardheavy

Resident (52)

hardheavy's picture

19-04-2011, 15:21

This model, DD PLUS Gradiente , has a " one big chip" processor made by Toshiba, to reduce cost, known as MSX ENGINE. I guess this unique processor has funcion of z80 and VDP. Take a look, please.

I read this article saying about mey board.

MSX DD PLUS had a black case and the problematic socketed chips was replaced by an ASIC one. Nevertheless, the RAM was mapped to a secondary slot and, although it was straight by the MSX standards, caused a lot of crashes with programs who searched for memory in the wrong place.

Maybe this can help you to understand the cause of problem.


By hardheavy

Resident (52)

hardheavy's picture

19-04-2011, 16:05

I find this article. The MSX Pus and DD PLUS was the last model made in Brazil. The earlier Expert models( 1.0 and 1.1) grey color case and keyboard, have Z80, sound chip and VDP separate. The DD PLUS and Plus models have MSX Engine custom chip. I guess this modification brought some incompatibility problems as write above:

The Expert Plus and DD Plus had a big incompatibility problem, that actually was not Gradiente's fault. Both machines used the MSX engine SMT chip, that made things easier to Gradiente assembly these computers, solving the bad contact problems of the socketed chips used in the previous Experts, and replacing three chips by one, but the MSX engine chip mapped the RAM to a internal secondary slot.

This was OK for the MSX standarts, but most brazilian software was written to run in Experts and Hotbits without secondary slots, and this resulted in many crashes.

The Expert users were also waiting for a MSX2 machine when the Plus was launched, and along with the common crashes, this made these machines not so popular.

The DDPlus uses a internal disk controller board that was quite similar to the external cartridge interfaces sold then. It also uses 16Kb for MSX DOS, resulting in 48Kb of ROM.

By hardheavy

Resident (52)

hardheavy's picture

19-04-2011, 16:08

The strange thing is that in some games (few) controls works great!.

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