Hi!

I have just upgraded my msx2+ a1wsx from 256ks (originarlly 64ks) to 512ks, as described in Adrian Oboroc guide.

The msx boots and shows it has 512ks, runs basic without problems, runs games without problems (i guess games doesn't use the extra 256ks)

The problem is with my sunrise cf interface, it works well with 256ks, but after upgrade it hangs after detecting cf cards, as if it has any problem booting msx-dos 2 (i think it's 2.2)

The utilities disk supplied with the sunrise cf interface (also msx-dos 2.2) hangs the msx after the msx-dos version message, but i have disks with msx-dos 1.1 and it works nice...

Does anyone knows if msx-dos 2.x has any problem with 512ks? does it loads at upper memory and that could cause trouble (as if one of the memory chips i used is not working...)

Is there a program to test the memory and be sure it's working fine?

Thanks!

HtDreams

CF works fine with 512k 1024k and 4Mo Ram in A1ST A1GT and 8280 with dos 2.30

load testram to this adress and check your MSX

http://www.alsoftware.com.br/adrianpage/index.php?page=msxsoft&section=util

Thank you!, i'll try the testram

Hi again

After runing the testram program (thank you again Jipe!) i've found that there are page failures from 16 to 31 pages (where the upper 256ks are, just the two memory chips i've installed) so i'm afraid i'll stick to 256ks and forget onboard memory upgrade i did it as the guide said and the computer informed of 512ks so it must be the 44256 memory chips not working fine...

have you sold the upgrade memory directly on the normal memory ?

have you respect the number of pins because the schema of chip 44256 is false (inverted) on Adrian guide ?

load a 44256 datasheet for compare

check if pin 51 and 52 on T9769 are on VCC

Hi!

I bought from arcade components (Usa online store) four 44256 chips (don't remember the speed, i think its 120ns ¿?)

I followed Adrian guide to upgrade to 256ks (it works perfectly)

Next i solded the other two 44256 over the firsts except pin 17 to connect to msx memory controller on pin 50, is this information incorrect? i must do this with other pin than 17?

Yes, i have pin 51 & 52 on VCC

Now i have pin 51 back at gnd, pin 52 on VCC and pin 50 connected to pin 17 of the upper 44256 chips (using two slim wires), so i have 256ks and everything works fine

I'll search for 44256 datashet...

Thanks!

HtDreams

have you desold pin 51 and raised it because is sold to pcb gnd inside IC

pin of 44256

1 D1.. o.. VSS 20
2 D2..........D4 19
3 WE/........D3 18
4 RAS/....CAS/ 17
5 NC.........OE/ 16
6 A0...........A8 15
7 A1...........A7 14
8 A2...........A6 13
9 A3...........A5 12
10 VCC..... A4 11

check if the pin 4 and the pin 17 is not inverted

Hi!

Yes, the pin 51 is raised and connected to pin 52 and VCC (so the msx knows has 512ks)

I installed four chips: http://www.arcadecomponents.com/catalog/item/2251646/1691199.htm

And as the first two installed over the board works fine i don't know how to verify the pin 17 is really CAS

Would I damage the computer if I change pin 17 for pin 4 to try?

Here i found a 44256 datasheet (from OKI) that marks pin 17 as CAS.

I'll check the manufacturer of the 44256 chips i've installed (i have to open the computer...)

Thanks!

just check pin because schema is inverted

100 ns is perhaps a little slowly

Ok, i'll try connecting pin 17 to lower chips and raising pin 4 on upper chips and connecting to pin 50 on memory controller

100ns is a little slowly? original memory chips were 120ns? (i don't know, i think so...)

Would it be good idea to get four 80ns 44256 and replace them? (the online store has 80ns chips at low cost, 1,49 euro each one)

Thanks for your help

don't connect pin 17 if you have respected the direction of pin

pin 1 is left up then you look memory upside and the notch is upper

_O_ pin direction _O_

Sorry, couldn't resist . By the way, what does the 'direction of the pin' have to do with connecting it or not? I don't quite get this part. I'd like to have my A1ST upgraded to 512kB too, sometime

sorry for this text in french for all users

je m'exprime mal en anglais

regarde sur le schéma de Adrian Oboroc : les pattes des mémoires sont inversées

normalement la 1ére patte du circuit est en haut a gauche , le circuit vu du dessus et l'encoche de détrompage en haut

vérifie bien que ton cablage est dans le bon sens et c'est tout

Translation attempt:

===
I express myself badly in English.

Look at the diagram of Adrian Oboroc: the pins of the memory chips are reversed

Normally the first pin of the chip is at the top left, the chip seen from above and the codification notch at the top.

Check thoroughly if your cabling is in the right direction and that's all
===

French speaking people can judge my translation qualities now. I have to admit to have looked up "encoche" and "détrompage"

thanks for translate