HX-34 memory upgrade

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By kansaizine

Supporter (13)

kansaizine's picture

16-09-2010, 18:59

Hi guys,

Recently, I bought Toshiba HX-34 MSX2 computer.
It have 64kb main memory.

I want to upgrade memory up to 128KB but I've no material.
I found empty memory pattern on main board, but I don't know
whether it only have to add memory and capacitor or some
jumper settings are also necessary.


I hope for someone's advice.

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By Manuel

Ascended (18734)

Manuel's picture

16-09-2010, 21:25

Wow, this is a pretty rare MSX outside of Japan!

By Repair-Bas

Paragon (1149)

Repair-Bas's picture

16-09-2010, 21:36

Try first with the memory chips and 2 capacitors (100nF)

By kansaizine

Supporter (13)

kansaizine's picture

17-09-2010, 03:10

Thanks manuel, Bas,

I'll try to add memory and capacitors first.
I report when completing it.

By sd_snatcher

Prophet (3503)

sd_snatcher's picture

17-09-2010, 04:24


Pease dump it's ROMs so the openMSX team can add this machine to their emulator.

By kansaizine

Supporter (13)

kansaizine's picture

17-09-2010, 04:44

Hi sd_snatcher,

Ok, I'll try to makerom.bas on the real machine.

By hap

Paragon (2040)

hap's picture

17-09-2010, 14:34

sd_snatcher, please be more careful making such requests to new forum members, it has a high possibility to be interpreted as unfriendly demands, even if unintentional.

kansaizine, don't feel obliged to go through the hassle of dumping roms and such, I'm sure manuel (openmsx guy) agrees. Welcome to the forum. Smile

By kansaizine

Supporter (13)

kansaizine's picture

17-09-2010, 15:54

Hi hap,

Thank you for worrying about me.
There's no problem, I also professional of MSX like you guys Tongue
I have the experience of MSX for 24 years and about ten MSX
is owned now. I am happy to contribute to the activity of openmsx.

I'm sorry, I'll try to upgrade memory first. after succeeded it,
next I'll try to run makerom.bas.

I wish to express my gratitude for everyone's consideration.

By Eugeny_Brychkov

Paragon (1184)

Eugeny_Brychkov's picture

17-09-2010, 19:36

Syunsuke, if you will be adding chips, use sockets so that in case of problems you can easily remove chips from the board. It will also help if you can make hi-res picture of the whole motherboard from both sides and post a link to them here.


Enlighted (5918)

NYYRIKKI's picture

17-09-2010, 19:49

Hmm... Many Japanese MSX2 computers don't have mappers, so test first if the mapper is present:

OUT &HFF,3 -> Crash = Add the chips
OUT &HFF,3 -> No effect = Forget the upgrade

By RetroTechie

Paragon (1563)

RetroTechie's picture

17-09-2010, 20:35

If it has empty place for ICs, it will probably have a mapper on board too (how else? 2 slots with 64K in each? oO ). Question then becomes whether that mapper is 'enabled' by default, or that you have to change solder bridge / jumper or something like that.

Just out of curiosity: what value does INP(255) return?

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