Yes the ST boot but with the intern program in rom

is difficult to burn a MSX

i think you make an error

can you take pictures of your RAM and board with a camera ?

in the GT /RAS2 pin 62 of R800 and /RAS3 pin 63 of R800 arent used , /RAS signal for RAM are on R372 R373

in the original ST only /RAS3 is used pin 63 of R800 and /RAS signal for the Ram is on R54

take a multimeter check on the 1Mo Ram you must /RAS pin 4 of memory in R54 for active /RAS3

Hey Leo, good night man;

I´m an electronics engineer too... and had modified my old MSXes in the past as a hobby: transformed my MSX to MSX 2.0, internal mapper, ram expansion, megaram expansion internally, internal slot expansion and so on... The truth is this was my first time opening a MSX after at least 3 years.. lol.. I´m getting rusty man! lol

What you said is 100% right, and I completely agree: Sometimes you need luck... and I really did the expansion in a hurry, I must admit.. it was in my living room carpet, in one morning! lol

By the way, when I turn the T-R on, my LCD lights on (when the LCD has no signal, it shows only the blue screen)... the T-R main power led lights on, and the LCD screen keeps lighted on in black color.

I´m beggining to suspect that burned SIMM-30 clips might be a good guess, as they are very old, therefore a friend of mine is sending some good SIMM-30 clips so I can test´em.

Will keep you guys posted.

All the best!

Fernando.

ok your electronic guy as well , so i wont feel ashamed to have burn msx me too!
More seriously , there is hope if the leds are showing a little , so your goal now is get a 256kb Tr back to life or still put that 1MB ?
Do you have means of inspection , like oscilloscope ?

on a normal MSX1 MSX2 MSX2+ if the ram is desolded you can put a ram cartridge in a slot and the MSX start

but on Turbo-R the ram is on R800 bus and not on Z80 bus and i don't know if ST or GT start

I don't know how the Turbo-R works exactly, but I'm pretty sure that should work. R800 DRAM mode won't work in that situation, so I'd expect the machine booting in R800 ROM or Z80 mode. Btw: do you have an external mapper? That would make things a lot easier.

Good night everyone.

It finally works! lol

The problems were a short circuit between pins DA8 and DA9 of the R800, and the inappropriate refresh time of the SIMM-30 that I was using, so I just had to clean the R800 terminals, and find a good 70 ns SIMM-30 (I was using a 60 ns before)

Here it goes the pics (it is not a final version yet.. so don´t mind the loose wires... lol )


http://img688.imageshack.us/img688/7398/p1010755.jpg

http://img24.imageshack.us/img24/9169/p1010759e.jpg

http://img695.imageshack.us/img695/6296/p1010760.jpg

http://img10.imageshack.us/img10/3162/p1010764wg.jpg

http://img24.imageshack.us/img24/2040/p1010768c.jpg

And finally... the 1 Mb DETECTION:

http://img690.imageshack.us/img690/462/detectou1mega.jpg

Thanks everyone for your help;

Best wishes;

Fernando.

Bravo , i am happy for you : the machine is not burnt and finally works ok !

The Best good end for this MSX : it's very hard to burn it !!

Fernando, congrats!