I've been trying for like 2 days to get this right, and I'm at my wit's end.
I have an original Just Breed famicom cart, and it tested working just fine with the original mask roms.
I thought I'd pop the Stealth translation into it via EPROMs, but all I have are MC27C801s (I got a box of like 40 of them from a friend who went to china).
I figured if I wired them up like I've seen on the net for MMC5 reproductions, and tied A19 and (and A18 on the CHR) to GND, the larger EPROMs would be limited to 512KB and 256KB, respectively, and run just fine.
Now, from what I've seen, the MMC5 eprom wiring is as follows:
Bend up pins 1, 2, 24, 30 & 31
pin 1 to hole 30 (grounded on PRG and CHR limit EPROM to 512KB)
pin 2 to hole 24
pin 24 to hole 31
pin 30 to hole 1
pin 31 to hole 2 (grounded on CHR with Pin 1 to limit to 256KB)
However, whenever I to run it on my NES, all I get is a solid color screen.
I can't get any sound, so it's obviously a PRG issue, but I've de-soldered the EPROM TWICE now, re-verified the content, erased and re-burned, then used ENTIRELY NEW CHIPS just to rule that out.
Please help!
I have an original Just Breed famicom cart, and it tested working just fine with the original mask roms.
I thought I'd pop the Stealth translation into it via EPROMs, but all I have are MC27C801s (I got a box of like 40 of them from a friend who went to china).
I figured if I wired them up like I've seen on the net for MMC5 reproductions, and tied A19 and (and A18 on the CHR) to GND, the larger EPROMs would be limited to 512KB and 256KB, respectively, and run just fine.
Now, from what I've seen, the MMC5 eprom wiring is as follows:
Bend up pins 1, 2, 24, 30 & 31
pin 1 to hole 30 (grounded on PRG and CHR limit EPROM to 512KB)
pin 2 to hole 24
pin 24 to hole 31
pin 30 to hole 1
pin 31 to hole 2 (grounded on CHR with Pin 1 to limit to 256KB)
However, whenever I to run it on my NES, all I get is a solid color screen.
I can't get any sound, so it's obviously a PRG issue, but I've de-soldered the EPROM TWICE now, re-verified the content, erased and re-burned, then used ENTIRELY NEW CHIPS just to rule that out.
Please help!