Hey, try to make a new tread here

The old one, more changed into how to upgrade memory than help with my problem.

MY a1st are already upgraded, and i need to know where i should solder the Resistor, it was soldered to the mainboard i think but i dont know where.

The Resistor is connected with a wire to the RAM IC.

The picture is a bit fussy

Photo here ===> http://mtxworld.dk/ram-a1st.PNG

If you can help please make a arrow on the picture, and mail it to me: cbpwr@hotmail.com

Anyone know what will happen if that resistor is not soldered ?

Will it only work in 256kb ?

-CB-

is difficult with this picture

if it's pin 4 of the memory i think is the RAS signal sold here because no CMS component

Thanks.

Anyone know what happend if that resistor is not connected ?

-Claus-

Jipe...

By the way is it possible to upgrade Turbo-R to 4mbyte ?

I saw your fine work about upgrade to 1mbyte.

-Claus-

No, 1MB is the maximum. There are no more address lines on the s1990.

yes adress mapper MA20 MA21 are in R800 but not in S1990

S1990
A15 L , A14 L , A12 L 64kb
A15 L , A14 L , A12 H 128kb
A15 L , A14 H , A12 H 256kb (ST)
A15 L , A14 H , A12 L 512kb (GT)
A15 H , A14 L , A12 - 1Mb

R800
A15 L , A14 L 64k*4
A15 L , A14 H 256k*4 (ST/GT)
A15 H , A14 L 1M*4
A15 H , A14 H 4M*4

1Mb in a MSX is enough 4 Mo is just for Megarom loader and i prefer a S-Ram (work better)

i have a 8280 with 4 Mo inside but that is not useful has large thing because the software does not exploit this memory

is just for say : i have a bigest memory in MSX (same i have a speed car but limit speed on way ;-) )

Hi

I know 4mbytes are very much for msx

512kb is very good for running many things.

But 1mbyte is for diskcopy.

...or SymbOS