help with sega dreamcast bios replacement

I can´t do it work on a ntsc-u va1, i tried two times, with different pre-flashed roms... I am afraid that I have broken my motherboard when i extract one of them, please help.

I use the image




of this tutorial http://www.mmmonkey.co.uk/console/images/sega/link83bios/44.jpgthis tutorial

Can someone give me some advice or new pics.
There are alternative points to use with some legs of the bios?

Sry 4 my english xD

 

my advice : also try ask about this problem in the English section on the DC-SWAT.ru site.

 

posted in dcswat, but i need help! thanks!

 

alternative points? thx

 

arent you missing the resistors?

 

Dont need resistors. Only when piggy backing.

 

I try with 2 motherboards and not success... i use all flash roms (i broke some legs...)

pin 22 of the motherboard are bad. alternative place to connect?​

 

you could try and follow the trace on the board for that pin a see where is connects, and there you go an alternative place.

 

yes, but i cant find the trace for pin 22
http://www.dc-swat.ru/forum/thread-1846.html

 

could you make it work?

I can't see very well cause your pics are a bit blurry!

As you know by now the Dreamcast mobo is extremely delicate and you can cut or burn traces without knowing, another thing is to check if you don't have cold joints, happens a lot on Dreamcast mods.

if you can take better pictures that will help a lot.
also if you speak Spanish I can help you in Spanish through PM or post your native language here, there may be someone that speaks your language that can help you.

 

Pin 22 is not connected to anything. That leg is unused.

 

hi all, i up this topic cause i meet the same problem. i bought some faulty DC from a guy who tried to install a freebios and there is some pin i'm pretty sure it can't be repeared. i just hope those are unused.



pin 1, 20, 22, 23, 25

from what i see, pin 1, 20, 22, 23 are unused, but what about pin 25 ?

thanks in advance.

 

ok i found the schematic and obviously the pin 20, 22, 25 are unused, pin 1 and 23 need to be connected to 5v so i have to find another point for them, i'm good ? thanks to confirm

 

Unless you have a VA0 board, then pins 1 and 23 need to wire to +3.3V and not 5V. There should be 2 vias just above the pin that have +3.3V on them.


Looking at the photo, you also appear to have a broken trace running just next to pin 1 - this might be worth checking, I think it's one of the chip select lines, so if its open it's going to cause some problems.

 

thank you TriMesh,

i started the repear, and i noticed after my post that it's VA1, i scratched a bit the board and discovered attachment to vias above the pin 23 like you saying

about broken trace, i got it fixed (i hope !) here is a pic :

 

Looks reasonable to me - the only possible problem is that having that jumper wire there for the broken track might make it hard to get the chip down close enough to the PCB.

 

very interested in this new info, please post if you have any progress

 

Liquid, Did you get it repaired?

 

two years later, i opened the console, and i check again the dreamcast, now i see that i need alternative places for pin 34 and 35...
xDDDD