Problem with my NMS8245 upgraded to MSX2+

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By Pablibiris

Paragon (1804)

Pablibiris's picture

23-02-2013, 19:44

Hi all!
I upgraded my NMS8245 to MSX2+ using a VDP 9958 and following this tutorial:
www.gilbertomsx.altervista.org/inglese/nms8245/msx2plus/msx2...
or this:
http://www.mediafire.com/view/?1dul39e4oww2s2x

I have one problem. When I load a tape game,when I reboot the computer,I can see this:
http://youtu.be/-XzlYnHIvzg

As you can see,when I reboot,I can see the right colours for 0,3 seconds,but immediately the colour change!
In this video,I put the primary colours (Blue,Green and Red).
When I put Green colour,the screen flashes...

This problem ONLY happens when I load a tape game (¿?) and after I reboot the computer.
If I wait 5 minutes with the computer turned off,the problem disappears.
Some idea for repair my MSX? :(

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By OeiOeiVogeltje

Paragon (1398)

OeiOeiVogeltje's picture

23-02-2013, 20:19

VDP kaputt?
was it a new one?
i did that modicifation too,twice (with a basic 3.0 eprom in it)
worked here

By Pablibiris

Paragon (1804)

Pablibiris's picture

23-02-2013, 20:24

The VDP supposedly is a new one...
But,if the VDP was broken,then I cant play any cartridge with the colours OK,right?
I can play normally and without problems,but when I load a tape game and I reboot..the problem appears Sad

By OeiOeiVogeltje

Paragon (1398)

OeiOeiVogeltje's picture

23-02-2013, 20:29

im affraid you need a software/hardware guru to solve that one.
im neither....
maybe is has something to do with basic 1.0 still present in the computer?
re-check all solderings (yes, again)

good luck

By Pablibiris

Paragon (1804)

Pablibiris's picture

23-02-2013, 20:40

The Rom 1.0 is still present but someone said to me that is not necessary to change it if you didn't want to work with the VDP in Basic.
Well,I go to re-check all solderings,thanks!!
Meanwhile I will continue waiting for a response from a guru MSX Tongue

By Jipe

Paragon (1500)

Jipe's picture

24-02-2013, 13:12

you use the composite video signal , have trying with a scart ?

By Pablibiris

Paragon (1804)

Pablibiris's picture

24-02-2013, 13:39

Hi Jipe! I'm connected to the TV with a SCART (I dont have the composite video cable)

By Jipe

Paragon (1500)

Jipe's picture

24-02-2013, 17:30

i have the same problem with synchro signal on a 8235/39 in old time solve by change component
i have the schematic of 8245/00/16 but missing the VDP sheet
i can help with this schematic
you can see the 8235 mod at : http://www.msxvillage.fr/download/download.php?id=121

By Pablibiris

Paragon (1804)

Pablibiris's picture

24-02-2013, 19:00

This Mod could work in a NMS8245?
Thanks Jipe!

By Jipe

Paragon (1500)

Jipe's picture

24-02-2013, 19:23

never trying in 8245 and the schematic of the VDP missing in the service manual (bad scan )
i can't help you for the rest if no schematic

By Pablibiris

Paragon (1804)

Pablibiris's picture

24-02-2013, 19:42

http://map.grauw.nl/resources/video/yamaha_v9958.pdf
This link could be useful for you?
Thanks again!

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