HB-F1XD Japanese MSX2 - Replace V9938 with V9958?

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By Colemu

Hero (535)

Colemu's picture

08-09-2012, 15:24

After using emulation for a while I have taken the plunge into real computing.
Baught a Japanese MSX2 (HB-F1XD) and am wondering if anyone has experience of this machine and could tell me if it is upgradeable.

I'm looking to upgrade the internal memory from 64k to 128k and possibly replace the V9938.

Any help would be appreciated.

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By Jipe

Paragon (1527)

Jipe's picture

08-09-2012, 15:41

Just replace the VDP V9938 by a V9958 is easy

but if you want the basic 3.0 inside is more difficult change the rom

By Colemu

Hero (535)

Colemu's picture

08-09-2012, 16:05

Do i really need to change the rom, i.e. will a game detect the presence of the V9958 without it?

By jltursan

Prophet (2578)

jltursan's picture

08-09-2012, 16:09

There's not too much info about the 128KB RAM upgrade for this machine Sad. Seems that the closest upgrade instructions are for the Sony HB-F9S; but I'm not sure at all...

By Jipe

Paragon (1527)

Jipe's picture

08-09-2012, 16:12

for basic game or basic program use special instruction : screen 10 , scrren 11 , screen 12 , set scroll etc basic 3.0 is required

with a game starting with L.M. command just VDP is required

By Colemu

Hero (535)

Colemu's picture

08-09-2012, 16:14

I searched all over but couldn't find any info either. I think I'll pull it apart and have a look at the mobo.
Is the V9958 just a straight replacement??

By Colemu

Hero (535)

Colemu's picture

08-09-2012, 16:26

I do have plenty of 27c256 Eproms and a few programmers if they would enable me to update the Basic from 2 to 3?? Will these suffice? If so, can you chaps point me in the right direction Question

By Jipe

Paragon (1527)

Jipe's picture

08-09-2012, 16:46

i think this is a big rom in the F1XD , check inside

for the VDP
pin 4 to GND
pin 27 to GND
pin 21 to pin 58 (+5V)

By Colemu

Hero (535)

Colemu's picture

08-09-2012, 16:58

Cheers, that seems quite straight forward. Ordered the V9958 chip, I'll have to get a socket too I think.

Now to investigate replacing Basic 2..... Wink

By Jipe

Paragon (1527)

Jipe's picture

08-09-2012, 17:44

the rom is a 128k x 8 LH531064 or LH531067
A0 to A16 adress bus directly drived by the MB64H444PF speed control

By OeiOeiVogeltje

Paragon (1402)

OeiOeiVogeltje's picture

08-09-2012, 18:04

Jipe wrote:

Just replace the VDP V9938 by a V9958 is easy

but if you want the basic 3.0 inside is more difficult change the rom

isnt the pinout of a v9958 different than a v9938??

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