faulty DC bios, pins owned - Версия для печати

faulty DC bios, pins owned - Версия для печати

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+--- Тема: faulty DC bios, pins owned (/thread-2113.html)

faulty DC bios, pins owned - Liquid - 22.03.2014 16:58

hi all, i bought some faulty DC from someone who tried to install a regionfree bios.

with the schematic, i noticed that pin 20, 22, 25 are unused, anyone can confirm ?

about pin 1 and 23, i have to find the 5v somewhere else, am i right ? any advice on this point ?

thanks in advance.

RE: faulty DC bios, pins owned - SWAT - 22.03.2014 17:27

All right. Get the power at any place, where you more convenient. For example from GD-ROM port, it's have 3.3v and 5v for any flashchips.

RE: faulty DC bios, pins owned - Liquid - 22.03.2014 17:34

awesome Mr SWAT.

many thanks for the fast answer Smile

RE: faulty DC bios, pins owned - Liquid - 22.03.2014 18:18

oh i just realized that it was a VA1 board and about leg 23 it must not be lifted. what should i do ?

edit : ok i scratched a bit the motherboard and found the attachment to the 3.3v via Big Grin

i hope my repear will be a success !

RE: faulty DC bios, pins owned - SWAT - 22.03.2014 20:45

Good luck Smile

RE: faulty DC bios, pins owned - Liquid - 23.03.2014 05:48

back for more,

i'm desperate for this one, i took time to do perfect soldering, tested everything with multimeter, all broken tracks are now ok and still don't boot Sad

i can't believe it's dead, SEGA never die, doesn't it ?

RE: faulty DC bios, pins owned - SWAT - 23.03.2014 09:59

I don't see where connected CE pin (not connected to reset and power with resistor). Check schematic http://www.dc-swat.ru/blog/hardware/16.html
You flash firmware to this chip before solder?

RE: faulty DC bios, pins owned - Liquid - 23.03.2014 19:32

hey swat, you mean i have to place 10k betwin reset and CE (lifted ?) ? i have 3.3k and 7.5k resistors only, i ll make 9,9k with 3 of them.

about the chip, the guy who failed gave it to me (hope he flash better than he solder ^^)

oh while i'm here, i started also the second DC failed, and doesn't boot too...i'm pretty sure all solders are fine.

RE: faulty DC bios, pins owned - SWAT - 24.03.2014 11:46

If CE pin not connected to the power (as in datasheet), the flash chip can will not work.
This motherboard with 5v or 3.3v bios chip version? You solder this pin direct...

Why you do not soldered it over a Sega bios ROM?
It will serve you in the future as a backup boot. if you write a non-working BIOS for example. Otherwise you will have to unsolder it again.
And you can be check motherboard work. If your DC boot fine with the original ROM, then new flash chip is damaged Sad

RE: faulty DC bios, pins owned - Liquid - 24.03.2014 15:00

like this ?

i got 3 faulty DC without original bios, all VA1 (3,3v), the same guy gave me 3 programmed chips with them, if i had choice i would do the piggyback.

in other hand, i found a post that show final pic of a working DC with full remplacment chip, i don't see any connection betwin CE and power.

http://www.assemblergames.com/forums/showthread.php?47458-Dreamcast-BIOS-chip-install-SUCCESS!

RE: faulty DC bios, pins owned - SWAT - 24.03.2014 16:23

Of course it's works if you replace 3.3v bios to other 3.3v flash chip, I'm just trying to find reason.
I'm sorry, I'm forget, you said me about motherboard before.
So maybe the flash chip can be broken before you Sad

RE: faulty DC bios, pins owned - Liquid - 24.03.2014 16:32

i just sent PM to Bad_ad84 for some programmed chip 3.3v, waiting shipping.

RE: faulty DC bios, pins owned - Gromber - 28.10.2014 02:36

any idea for alternative place for pins 34 and 35, thanks,

RE: faulty DC bios, pins owned - SWAT - 28.10.2014 09:20

(28.10.2014 02:36)Gromber писал(а): any idea for alternative place for pins 34 and 35, thanks,

Try find it here http://www.dc-swat.ru/download/doc/schema/Sega_Dreamcast_schematic_diagram.pdf