I'd like to apply the fan translation of Akira to my Famicom cart. I already traced out all the pins so I'm not worried about wiring, although there are some things I'm concerned about before I start desoldering:
The fan translation expands the PRG from 128 kilobytes to 256 kilobytes. I'm guessing that this shouldn't be a problem, but I couldn't find a lot of information about this.
Also the game uses two 128 kilobyte CHR mask ROMs, and it looks to be controlled by a 74HC139AP decoder. I'm sort of a layman in terms of how this particular Taito chip handles this, but from what I traced out it appears that the TC0190 sends inputs to the 74HC139AP to decide which CHR ROM chip is currently needed and switches as necessary. This is all guesswork on my part.
What I'd like to know is, could I use a single 256 kilobyte EPROM like a 27C020 and bypass the 74HC139 by soldering leads directly to the TC0190? Or is the program expecting two CHR ROMs and the 74 chip to be in the circuit to function properly?
Finally, assuming I HAVE to use a pair of 128 kilobyte EPROMs for the CHR ROMs, how do I split the CHR file? Every ROM utility I can find spits out a 256 kilobyte CHR bin file, and I didn't want to assume I could just download a generic file splitter program and divide it in two and burn the EPROMs.
The fan translation expands the PRG from 128 kilobytes to 256 kilobytes. I'm guessing that this shouldn't be a problem, but I couldn't find a lot of information about this.
Also the game uses two 128 kilobyte CHR mask ROMs, and it looks to be controlled by a 74HC139AP decoder. I'm sort of a layman in terms of how this particular Taito chip handles this, but from what I traced out it appears that the TC0190 sends inputs to the 74HC139AP to decide which CHR ROM chip is currently needed and switches as necessary. This is all guesswork on my part.
What I'd like to know is, could I use a single 256 kilobyte EPROM like a 27C020 and bypass the 74HC139 by soldering leads directly to the TC0190? Or is the program expecting two CHR ROMs and the 74 chip to be in the circuit to function properly?
Finally, assuming I HAVE to use a pair of 128 kilobyte EPROMs for the CHR ROMs, how do I split the CHR file? Every ROM utility I can find spits out a 256 kilobyte CHR bin file, and I didn't want to assume I could just download a generic file splitter program and divide it in two and burn the EPROMs.