Goldendark007 | 4 Posted July 23, 2020 Share Posted July 23, 2020 It has been a while since I have been making anything but I wanted to use some spare donor boards I have lying around for a few projects. It has been a few years since I've made a repro and I obviously cannot easily access the information from NA, so I was wondering if anyone has the PINOUT for a 352026 Konami MMC3 (TLROM) PCB. I have a 27c010 for a CHR and a 27c020 for PRG. I think the CHR wiring is just the same as the UNROM wiring for a 27c010, but I can't recall how to wire a 27c020. Is it just the same? Thanks! Link to comment Share on other sites More sharing options...
Lincoln | 230 Posted July 23, 2020 Share Posted July 23, 2020 For both sides it should be pins 1 up 2 - hole 22 24- ground 30 up 31 up (for clearance) 32- hole 28 For a 2mb chip pin 30 will have to go to the mapper for prg a17 a 32 pin eprom won't fit in the prg space without cutting the shell, keep that in mind before you get too deep 1 Link to comment Share on other sites More sharing options...
Goldendark007 | 4 Posted July 23, 2020 Author Share Posted July 23, 2020 27 minutes ago, Lincoln said: For both sides it should be pins 1 up 2 - hole 22 24- ground 30 up 31 up (for clearance) 32- hole 28 For a 2mb chip pin 30 will have to go to the mapper for prg a17 a 32 pin eprom won't fit in the prg space without cutting the shell, keep that in mind before you get too deep Lincoln - it makes me smile to see that you are still around to answer my questions - even 7-8 years deep. I already cut the nub in the shell to fit the PRG. My plan is to do CHR on the front of PCB and to do the PRG on the back, upside down, and wire legs 17-32 to the respective locations. I have done this in UNROM to UOROM conversions. For pin 30 going to the mapper, does this mean I need to wire to the MMC3B or to pin 17 itself? Or does it go somewhere else entirely? Sorry - as I have said, it's been a while and I have never used this PCB before. Link to comment Share on other sites More sharing options...
Lincoln | 230 Posted July 23, 2020 Share Posted July 23, 2020 It will need to go to the mapper. The specific mapper pin will be for "prg a17". That pin may have a trace you can wire to for easier access (would not expect it), but it isnt currently going to the prg slot as there's no corresponding pin on the mask rom. Placing the chip upside down is an interesting idea, ive done that with ram chips but not eproms. Link to comment Share on other sites More sharing options...
Goldendark007 | 4 Posted August 5, 2020 Author Share Posted August 5, 2020 On 7/23/2020 at 7:30 PM, Lincoln said: It will need to go to the mapper. The specific mapper pin will be for "prg a17". That pin may have a trace you can wire to for easier access (would not expect it), but it isnt currently going to the prg slot as there's no corresponding pin on the mask rom. Placing the chip upside down is an interesting idea, ive done that with ram chips but not eproms. Thanks for clearing that up. Finished it up last night - worked perfectly. It was pin 25 on the MMC3. Will post/edit later with some pics. Thanks again!! Link to comment Share on other sites More sharing options...
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