Drop in replacement eproms

Discuss hardware-related topics, such as development cartridges, CopyNES, PowerPak, EPROMs, or whatever.

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ironsniper1
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Joined: Sat Jan 16, 2021 3:47 pm

Drop in replacement eproms

Post by ironsniper1 » Sat Jan 23, 2021 10:26 am

hey everyone

is there any 32 pin eproms that are a drop in replacement on nes carts that dont require wiring? not saying i couldnt do the wiring but just curious, i know the 29c256 is a drop in replacement for some as i used them to fix an excitebike cart, but what about games that use chr ram or that use 32pin mask roms?

lidnariq
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Re: Drop in replacement eproms

Post by lidnariq » Sat Jan 23, 2021 11:26 am

Nope.

You could design an external PCB that would do this, but there were no preexisting programmable memories that put A16 on pin 24.

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poorstudenthobbyist
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Re: Drop in replacement eproms

Post by poorstudenthobbyist » Sat Jan 23, 2021 11:34 am

lidnariq wrote:
Sat Jan 23, 2021 11:26 am
Nope.

You could design an external PCB that would do this, but there were no preexisting programmable memories that put A16 on pin 24.
Shameless plug time
Check out my website for NES, SNES, and Genesis tutorials here. And visit my store for some custom tools and boards for making games here.

You can also follow me on Twitter for infrequent updates and bad jokes!

ironsniper1
Posts: 35
Joined: Sat Jan 16, 2021 3:47 pm

Re: Drop in replacement eproms

Post by ironsniper1 » Sat Jan 23, 2021 12:47 pm

poorstudenthobbyist wrote:
Sat Jan 23, 2021 11:34 am
lidnariq wrote:
Sat Jan 23, 2021 11:26 am
Nope.

You could design an external PCB that would do this, but there were no preexisting programmable memories that put A16 on pin 24.
Shameless plug time
does that fit in a standard cart shell?

EDIT im stupid and didnt read disregard

EDIT 2 can I use a 29c040 flash eprom rather than the one that needs to be erased via a uv eraser?

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poorstudenthobbyist
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Re: Drop in replacement eproms

Post by poorstudenthobbyist » Sat Jan 23, 2021 2:18 pm

ironsniper1 wrote:
Sat Jan 23, 2021 12:47 pm

does that fit in a standard cart shell?

EDIT im stupid and didnt read disregard
No worries. It fits on standard Nintendo boards, but I think some Konami games won't fit. And some boards (like EKROM, off the top of my head) have too many parts in the way for one/both of the chips. But it fits most.
EDIT 2 can I use a 29c040 flash eprom rather than the one that needs to be erased via a uv eraser?
It'll most likely work as a drop-in, but pins 1 and 31 are flipped between the UV EPROMs and the flash chips. So if it doesn't work, just cut those two pins and rewire them to flip their positions. Should only be an issue on larger ROMs (512k)

New version coming soon with solder pads on the back to take care of that, most likely this week.
Check out my website for NES, SNES, and Genesis tutorials here. And visit my store for some custom tools and boards for making games here.

You can also follow me on Twitter for infrequent updates and bad jokes!

ironsniper1
Posts: 35
Joined: Sat Jan 16, 2021 3:47 pm

Re: Drop in replacement eproms

Post by ironsniper1 » Mon Jan 25, 2021 7:12 am

poorstudenthobbyist wrote:
Sat Jan 23, 2021 2:18 pm
ironsniper1 wrote:
Sat Jan 23, 2021 12:47 pm

does that fit in a standard cart shell?

EDIT im stupid and didnt read disregard
No worries. It fits on standard Nintendo boards, but I think some Konami games won't fit. And some boards (like EKROM, off the top of my head) have too many parts in the way for one/both of the chips. But it fits most.
EDIT 2 can I use a 29c040 flash eprom rather than the one that needs to be erased via a uv eraser?
It'll most likely work as a drop-in, but pins 1 and 31 are flipped between the UV EPROMs and the flash chips. So if it doesn't work, just cut those two pins and rewire them to flip their positions. Should only be an issue on larger ROMs (512k)

New version coming soon with solder pads on the back to take care of that, most likely this week.
thanks for that, i did purchase one of your boards so i look forward to using it

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poorstudenthobbyist
Posts: 231
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Re: Drop in replacement eproms

Post by poorstudenthobbyist » Tue Jan 26, 2021 11:01 pm

ironsniper1 wrote:
Mon Jan 25, 2021 7:12 am
thanks for that, i did purchase one of your boards so i look forward to using it
I thought that was you haha.
Thanks! :beer:
Check out my website for NES, SNES, and Genesis tutorials here. And visit my store for some custom tools and boards for making games here.

You can also follow me on Twitter for infrequent updates and bad jokes!

ironsniper1
Posts: 35
Joined: Sat Jan 16, 2021 3:47 pm

Re: Drop in replacement eproms

Post by ironsniper1 » Fri Feb 05, 2021 1:20 pm

poorstudenthobbyist wrote:
Tue Jan 26, 2021 11:01 pm
ironsniper1 wrote:
Mon Jan 25, 2021 7:12 am
thanks for that, i did purchase one of your boards so i look forward to using it
I thought that was you haha.
Thanks! :beer:
i got your adapter board in as well as my replacement eprom for the copy of mega man 2 i have and it works, still have the issue as when i got the game but atleast i have an eprom and adapter to use if i need too! thanks!

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