MegaCD under the knife, surgeon's opinion needed

[Emperor Udan]

Years ago, I buy one Jap Mega CD very first run.
After months of good service, one night, I yelled very loud. (like in the movies you know, with arms in the air and stuff...)
I messed up with PSU and had fried my so beautiful Mega CD.

Black screen, no sound, no light, no disc turning...

Years later, i goes to a TV repairman with the AC board.
He test everything on it and fix them, except chip I guess.
Return to house, test: OMG screen of the sky!



But thats all, no sound and nothing more.
I said to myself: ok I try I lose.
I think the bios eprom may have been damaged.

Nowadays, Everdrive and Region Free Mega CD Bios make me mad!
Everdrive is mine but my Mega CD is still between life and death, and I need your help here.

I talked a little bit of my problem in the Mega-CD real region free thread and move it here, better place to bring back to life.

Some said that the problem was either from the transfer board, either from the flat cable between bios board and CD-Rom drive board.
After a real and deep inspection, I discovered that the inside of the machine was dirty as possible and bios board seemed to have some rust on it.


Situation:

If you prefer, here is the archive of all pictures below: Download.

• Transfer board

Seem clean.

• CD-Rom drive board

Seem clean too; dont want to dissect it.

• AC Board

Very dirty at some area but seem good.
On the 6th picture, it has a hit but continuity is good.

• Bios board

Here are coming problems...and a lot.
As you can see, some points seems unsoldered.
They are very, very small, and if my guess is right, work will be hard, very hard. :banghead:

What do you think about it?

• Bios Socket

Seem good.

• Bios Eprom

Written on it:
MBM27C1024-15Z
9147 R63

So here we are, maybe a rusty bios Board.
I try different Megadrive and it's always the same:
Power on, and after 1 second, sky appear but nothing more, no sound, no in front light, no turning disc.

What do you think about it?