HX-34 memory upgrade

Supporter (13)

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.

http://twitpic.com/2ozmzn

I hope for someone's advice.

!login ou Inscrivez-vous pour poster

Par Manuel

Ascended (18784)

16-09-2010, 21:25

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

Par Repair-Bas

Paragon (1153)

16-09-2010, 21:36

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

Par kansaizine

Supporter (13)

17-09-2010, 03:10

Thanks manuel, Bas,

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

Par sd_snatcher

Prophet (3505)

17-09-2010, 04:24

@kansaizine

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

Par kansaizine

Supporter (13)

17-09-2010, 04:44

Hi sd_snatcher,

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

Par hap

Paragon (2040)

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.

Par kansaizine

Supporter (13)

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
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.

Par Eugeny_Brychkov

Paragon (1195)

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.

Par NYYRIKKI

Enlighted (5918)

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

Par RetroTechie

Paragon (1563)

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? ). 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?