Mega-CD real region free on game discs

l_oliveira: yep but believe me it was with my bios reading ok, I put the 4mb bios it didn't read. I left it powered off for about 20 minutes and tried again and it worked.ray:

 

There are several different capacitors on the board but I suppose most of them are 10uf 16v. They all have their values written on them. :thumbsup:

Now, as per the bios, if you write just 128KB of a 512KB chip, you're supposed to connect the two extra address lines to the ground (GND) or otherwise the system will glitch badly. Even if you're using the chip with 4 copies of the bios burnt in it, you SHOULD connect the two excess address pins either to GND or VCC. :shrug:

 

How do i know witch two excess address pins i should connect?
Is it to ground or VCC?

 

A17 and A16 are your pins. VCC=1 (+5v) VSS=0 (GND)

 

I replaced all the capacitor on the motherboard and grounded pins 39 (A17) and 38 (A16).



Put it back together and BAM first try! So if you have problems with your region free bios just ground pin 38 and 39. It is also recommended to replace the caps. I am crying blood right now! I am so happy that it works again! I wanna thank DarthCloud and Eddyiori for helping me! Sorry for trashing the tread



But my biggest thank you to l_oliveira for saving my Mega CD and making the region free bios! I love it! I kneel before you.

EDIT: Thank you raq for making this possible! ray:

 

Don't forget to thank raq from spritesmind.net (he posts here too) for taking the time of debugging the sub CPU bios and devising the simple patch to a conditional branch which makes this whole region free bios thing possible. :thumbsup:

His original thread here:

http://gendev.spritesmind.net/forum/viewtopic.php?t=726

 

Hello!

where is the bios on the sega cdx?

http://www.obsolete-tears.com/switcher-un-sega-multimega-dossier-85.html

 

The SEGA chip marked "MPR-XXXX" (I don't know the right numbers but it start with MPR) right above the right controller port on the main board... :thumbsup:

 

What type of EPROM for replacement ?
27C1024 ?

 

Yes. ROM file should be byte swapped (68000 is big endian). :thumbsup:

 

Bad_Ad84 isnt it possible to burn the Sega CDX bios on to a:

MX S004632
29F800TMC-90
2C3487L0A1
TAIWAN ?

 

Probably, but the pin out is not the same. you would need to spider wire it in.

IMO not worth the hassle, just get the correct chip?

 

Is there a similar chip that can replace the:

SEGA
MPR-16140-T
5N00-15-L687
9401EAI JAPAN ?

 

MX27C1024 is the right pinout if i remember correctly. but the original chip is a sop40 and has no direct replacement (that I could find anyway)

MX27C1024 and wiring it up would be your best choice as its right pinout - unless someone else knows another chip

 

Ok thank you! It would be nice to find a good replacement chip. I do not whant my machine to look like this.
http://wolfsoft.de/wordpress/wp-content/uploads/2010/04/mm19.jpg

Is there a Multi Mega region free bios?

 

use the usa cdx bios?

you would need someone to make a tsop to sop40 adapter for a clean install, unless someone knows a better replacement

 

sega cd 2 US compatible with the bios jap region free?

 

100%.

The only thing you need to observe is if your system is of the lid type or tray type and use the proper bios for the system you have ...

If you put a lid type bios on a tray system you will be unable to open the tray to change the game ... :lol:

But well ... That's kind of obvious, no ? :thumbsup:

 

Is anyone selling it here? I have a Sega CD Model 1.

 

Selling the work of others (SEGA) is unethical so I choose to make it available publicly.

If someone charges you for the work of putting it into a EPROM chip, it's fine with me. :thumbsup:

Link:

http://www.4shared.com/file/0HXCyFYT/Hacked_MEGACD_BIOSES.html