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

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By sp4

Master (214)

sp4's picture

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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By Leo

Paragon (1236)

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19-04-2010, 19:12

By Leo

Paragon (1236)

Leo's picture

19-04-2010, 19:12

did you try msx hans o site ?

By usuario_msx2

Paladin (756)

usuario_msx2's picture

19-04-2010, 19:18

http://msx.retro8bits.com/

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

By Leo

Paragon (1236)

Leo's picture

19-04-2010, 20:55

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

By RetroTechie

Paragon (1563)

RetroTechie's picture

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)

By sp4

Master (214)

sp4's picture

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 ?

By Jipe

Paragon (1546)

Jipe's picture

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

By Leo

Paragon (1236)

Leo's picture

20-04-2010, 19:36

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

By Manuel

Ascended (18694)

Manuel's picture

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

By Repair-Bas

Paragon (1149)

Repair-Bas's picture

20-04-2010, 19:49

CryingCryingCryingCrying

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