Research an electric schematic of the mother board for msx vg-8020

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Par sp4

Master (214)

Portrait de sp4

19-04-2010, 18:37

Hi, i' m searching the electric schematic of the mother board for msx vg-8020.
Is there someone than can help me to search any links or other material about this
schematic?
Please, for me it's important for repair the mother board.
Thank.

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Par Leo

Paragon (1236)

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19-04-2010, 19:12

Par Leo

Paragon (1236)

Portrait de Leo

19-04-2010, 19:12

did you try msx hans o site ?

Par usuario_msx2

Paladin (755)

Portrait de usuario_msx2

19-04-2010, 19:18

http://msx.retro8bits.com/

did you try to connect Leo?, many sections are now offline.

Par Leo

Paragon (1236)

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19-04-2010, 20:55

it is explained on the left column of the site. i have not visited the site since last month .

Par RetroTechie

Paragon (1563)

Portrait de RetroTechie

20-04-2010, 16:39

For what exact type of VG-8020 do you want a schematic? There exist different 'sub-versions' labeled as VG-8020/nn (see label on case bottom). These all look the same on the outside, but can be wildly different on the inside (lots of discrete IC's in some older versions, MSX-engine + just a few IC's in later versions). Obviously you need this info to grab the right schematic. Smile2

Btw. do you have an idea what's broken? Often you don't need any schematic to fix a machine like an MSX1... (speaking from experience here)

Par sp4

Master (214)

Portrait de sp4

20-04-2010, 18:29

Thank you RetroTechie, my msx model is exactly vg-8235/00.
I have maden any measurement inside it: i have tested the ck-pin of CPU z80, its frequency is 0 Hz,(it's strange) i have maden it with keyboard unconnected. I think than the problem is in the ck generator.
What do you think about this problem ?

Par Jipe

Paragon (1502)

Portrait de Jipe

20-04-2010, 19:24

the V9938 generate CPUCLCK on pin 8 -> resistor R39 47 ohms -> O in pin 29 S3527 -> O out pin 30 S3527 -> R7 47 ohms -> Pin 6 Z80

Par Leo

Paragon (1236)

Portrait de Leo

20-04-2010, 19:36

I guess you have you checked +5v as well ?

Par Manuel

Ascended (18150)

Portrait de Manuel

20-04-2010, 19:39

Hi, i' m searching the electric schematic of the mother board for msx vg-8020.
and then
Thank you RetroTechie, my msx model is exactly vg-8235/00.

oO

Par Repair-Bas

Paragon (1125)

Portrait de Repair-Bas

20-04-2010, 19:49

CryingCryingCryingCrying

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