Hi, im using a jap secret of mana cart as a donor cart to make secret of mana 2 and when i opened it up i found that the mad 1 chip was replace with a 74LS139. can any one tell me how i can hock up the 74LS139 with 4 eproms?
You should use a flash cart instead of destroying these carts, it would be much easier and work just as well.
Im not a big fan of flash carts, i don't know why there just some thing about them i don't like! and im not really destroying old carts im just replacing the game :L
What is the difference between using a flash cart and ripping apart one of your own carts and throwing on an EPROM? Essentially they are the same thing. You can buy a flash cart for $60 and throw your own label on the cart. It would be exactly the same.
Not that I condone this but all you need to do is disconnect the ROM select signal (/CE) attach that to ANOTHER 74139's enable (/G). Connect that specific decoder's (the chip contains two) selects to the most significant address lines for 32M (A20,A21), connect Y0 to the first 8M ROM, Y1 to the second etc..
