Upgrade MSX2 to MSX2+ (Yamaha YIS-503III) КУВТ2

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By DJs3000

Expert (104)

DJs3000's picture

18-02-2015, 22:38

Hello everyone!
I want to remake the MSX2 to MSX2 + from Yamaha YIS-503III.


I replaced the VDP V9938 to V9958. I made a jumper on video processor 4,20,27 pin and 21,58 pin. Connect the signal WITE. Through impulse diode connected with Z80 (24pin) to V9958 (26pin).

After these changes without problems run games for MSX2 + but the display image is of poor quality (noise and ripple).
Please tell me how to improve the display image quality? http://www.youtube.com/watch?v=KpBNH6O6kLk
I went ahead and replaced the bios + basic.rom and ext.rom of MSX2 +.

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By Daemos

Paragon (1668)

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18-02-2015, 22:44

try this thread

By DJs3000

Expert (104)

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18-02-2015, 23:49

Daemos, thenx i check tomorrow Smile

By DJs3000

Expert (104)

DJs3000's picture

19-02-2015, 15:30

Result:

video

By DJs3000

Expert (104)

DJs3000's picture

19-02-2015, 16:37

Video is not visible but the picture quality was very good Smile

By Daemos

Paragon (1668)

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19-02-2015, 19:35

LOOOOL!! what a huge cap! little bit of an overkill but just leave it the way it is if your problem is solved.

By jltursan

Prophet (2115)

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19-02-2015, 19:58

Yep, he has used 220uF instead 220nF; but seems that it works Smile

What's the resistor value used, the one suggested by Daemos (100K)?

By DJs3000

Expert (104)

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19-02-2015, 21:49

Capacitor which was established in the store Smile resistor exactly 100к. Can replace these two elements on the ceramic capacitor 0.1uF and install it parallel to the resistor R311.

By DJs3000

Expert (104)

DJs3000's picture

19-02-2015, 22:25

There is another serious problem. This computer produced Yamaha for schools of the Soviet Union. After the installation of the BIOS from the MSX2 + about half the buttons do not match Smile
I set the BIOS to "Sony F1-XV". Possible to change the new bios button on the keyboard to match? I can attach the old and the new bios.

By Manuel

Ascended (14788)

Manuel's picture

19-02-2015, 22:27

Looks like you need to transplant some keyboard matrix stuff from the old BIOS to the new one Smile

By DJs3000

Expert (104)

DJs3000's picture

19-02-2015, 22:51

Manuel wrote:

Looks like you need to transplant some keyboard matrix stuff from the old BIOS to the new one Smile

Yes! But what and how? Can someone help?
old bios
new bios

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