MSX Turbo-R FS-A1ST with JIPE upgrade - won´t boot after memory upgrade

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By gallego

Supporter (6)

Аватар пользователя gallego

04-11-2009, 12:26

Good Morning Everyone.

I´ve tried to upgrade my FS-A1ST memory to 1 Mb using JIPE/HANSO circuit located at http://msx.retro8bits.com/msxdocs/msxturbor1mb.pdf

I´m using 2 memory ICs type TMS44400, with 60 ns access time, extracted from a SIMM-30.

The problem is that, after the upgrade, the MSX won´t boot anymore.

I´ve double-checked the circuit and pinouts, and everything is exactly accordinly to JIPE instructions.

Does anyone have an ideia of would could it be?

Thanks in advance;

Fernando - Brazil

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By Eugeny_Brychkov

Paragon (1232)

Аватар пользователя Eugeny_Brychkov

04-11-2009, 13:03

Well, looking to the diagram for ST I would say there should be no reason for such behaviour because all other relevant schematics stay in place without modifications - /RAS, /CAS and /WE. Check again, you should have done something wrong, and most probably with LS367 so it has steady low level at the output and hangs data bus's bit 5 (this is actually the only one output of this schematic!).

Another suspicion is 60 versus 70ns, wrong timing also can be the cause for non-operation (however I checked refresh timing should be the same). If you prove that you wired everything correctly and the circuit does not hang any lines, then it would probably be memory chips. BTW, they sometimes die (for example, from static electricity).

By Jipe

Paragon (1594)

Аватар пользователя Jipe

04-11-2009, 22:12

the board with 74LS670 is optionnal with DOS2 just for decode mapper for DOS1

if you cut wire pin 18 R800 to ground , shunt 22 S1990 to 18 R800 , shunt 33 R800 to pin 5 memory , sold resistor 1K on R41 , sunt R229 , desold R206 , shunt R206 with A14 and sold memory the ST start

can you make photos of modification and memory

added : the ST work with 60ns but not the GT (required 70ns)

By OeiOeiVogeltje

Paragon (1426)

Аватар пользователя OeiOeiVogeltje

04-11-2009, 23:11

id like to see detailed pictures of it to

By gallego

Supporter (6)

Аватар пользователя gallego

06-11-2009, 13:13

Thanks for your feedback my friends.

I believe that I´ve probably bricked it somehow through the installation process, because I´m trying now to insert the original 256k back to the sockets that I´ve installed, and it doesn´t seem to work.

Also, I´ve tried with different 70 ns and 60 ns simm-30 that I have, and nothing as well.

I´ll take some high-def pictures, and will record a you-tube video of the t-R behavior this weekend, and will post it here, so you could try to help me to figure it out where it could be the problem.

Thanks in advance;

By Jipe

Paragon (1594)

Аватар пользователя Jipe

06-11-2009, 15:27

check your wires between memory , a past i have breaking wire then desold memory , if breaking make a shunt

By OeiOeiVogeltje

Paragon (1426)

Аватар пользователя OeiOeiVogeltje

06-11-2009, 16:40

jipe
could you make a dumb list for me?
connect wire from r1 to r 4
connect pin 2 to pin 4
cut pin 6 of IC 35

something simple like that?
i dont need to know what im doing, i just need to know what i need to do

thanks

oh
and hi-res pics would help too

By Jipe

Paragon (1594)

Аватар пользователя Jipe

06-11-2009, 17:25

is not easy to make a quickly dumb list because i have not a Turbo-R open near me and some signal don't connect to a composant but directly on a hole in board
you can see hi-res picture in hnostar n°43 july 1999

if you mount directly chips a special shunt is required R373 left connect to R372 right with a cms resistor
is for bank 0 of R800 memory ( is on Hanso PDF )

and IC31 pin 5 , IC32 pin 5 must be connected to IC30 pin 5 ( is not on Hanso PDF )

the first schematic is for a simm 30 ( see on hnostar ) and modified for direct chips

By OeiOeiVogeltje

Paragon (1426)

Аватар пользователя OeiOeiVogeltje

06-11-2009, 20:31

heh
i dont understand a word youre saying

composant
shunt?
cms resistor?
r800 memory?

i have no idea

but its not important
if you can make me such a list id be very gratefull
it doesnt have to be tomorrow or next week

By Jipe

Paragon (1594)

Аватар пользователя Jipe

07-11-2009, 12:39

sorry i'am french i my english is very poor

composant is a electronic spare
shunt is a little wire nude
cms is "composant monté en surface" in french
on Turbo-R the memory chip is directly on R800 bus
see schematic on Hanso web
if you cannot read a schematic , not modify your MSX because you don't find error or breaking wire after

i have same difficult for understand the english post and babel fish don't help for technical language

By jltursan

Prophet (2619)

Аватар пользователя jltursan

07-11-2009, 13:26

cms is "composant monté en surface" in french

SMD component then :)

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