32 pin EPROM to 28 pin pcb

[Polar Hacker]

Okay, so I got a NROM 256 pcb and a 27C1001 EPROM. I was stupid however, because I didn’t take into consideration that the pcb only has room for 28 pins, and my chips are 32. Is there a way to convert this? I found this, is this correct?:

pin 1 unconnected
pin 2 -> hole 22 (under eprom pin 24)
pin 24 -> GND
pin 30 -> can be left down in hole 28
pin 31 -> unconnected, or on some chips may need to be 5V
pin 32 -> hole 28 (under eprom 30) for 5V

If not, what do I need to do? (Or can I even do this?)

Thanks!

Polar Hacker

[lidnariq]

27C1001 holds 128 KiB of data; NROM can only address 32 KiB of PRG and 8 KiB of CHR.

The standard solution is to duplicate the data until it is the same size as the 'PROM, and then tie all unused lines high or low.

[Polar Hacker]

27C1001 holds 128 KiB of data; NROM can only address 32 KiB of PRG and 8 KiB of CHR.

The standard solution is to duplicate the data until it is the same size as the 'PROM, and then tie all unused lines high or low.

Thats what I was going to do. So after I program the chips, what pins do I rewire and such?

[tepples]

You lift the pins on the chip whose signal differs from those in the holes on the board at the same position. (These are usually pins 1, 2, 24, 30, and 31.) Then you wire those pins to the empty holes by matching up the signals.

• ROM pinouts: What signal is on each pin or hole
• NES EPROM conversions: A cheat sheet for the most common boards
• Advanced MMC3 NES Reproduction: A start-to-finish tutorial with pictures

[Polar Hacker]

You lift the pins on the chip whose signal differs from those in the holes on the board at the same position. (These are usually pins 1, 2, 24, 30, and 31.) Then you wire those pins to the empty holes by matching up the signals.

• ROM pinouts: What signal is on each pin or hole
• NES EPROM conversions: A cheat sheet for the most common boards
• Advanced MMC3 NES Reproduction: A start-to-finish tutorial with pictures

Okay then, so I was correct then. Thank you! I think i'm going to be sticking to new pcb instead of donor carts now. Much easier and better