Need help with eprom and konami pcb

Door itozzz

Expert (67)

afbeelding van itozzz

29-04-2022, 14:25

Hi to everyone.
Let's see if an expert on the subject can guide me, I'm trying to flash a konami EPROM (specifically the goonies) that has an eprom 27256 inside it, I have de soldered the EPROM, I have erased it with uv but when I read it with willem some boxes me BF comes out and the rest with FF (as if it were empty), before that I have made a copy of the EPROM (.rom) and the fmsx reads it correctly. I have also tried with a 27c256 EPROM and it records and verifies it correctly but when I put it in the original pcb it does not start (the msx boot letters remain and strange characters come out).
I have tried with a custom pcb:

And I can't get it to work either, I also tried other roms that don't go over 64k and the same thing happens.
Can someone guide me or tell me what I'm doing wrong?

Original Goonies konami PCB

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Van Wierzbowsky

Guardian (3648)

afbeelding van Wierzbowsky

29-04-2022, 15:35

Swapping first and second 16kb of the ROM might help.

Van itozzz

Expert (67)

afbeelding van itozzz

29-04-2022, 21:14

Yess thats the key!! Big smile
Works fine very much thanks.