Not sure if this or the hardware subforum would be best, here it goes.
So, a handful of months back the fan translation for Lagrange Point on Famicom was completed, but due to the special chip/mapper in the cart it is not currently compatible with any NES/Famicom flashcarts.
I've seen some people taking the "repro" approach of taking the original cart and replacing the original ROM chip with an EPROM that has the translated rom file programmed on it so it can be played on original hardware.
I'll start with the issue the give details on my research/troubleshooting to see if anybody has ideas.
Issue: When the EPROM is installed in the cart, the system just boots to a solid color screen (the same as if no cart is inserted).
Troubleshooting: Desoldered the ERPOM after things weren't working, installed a precision socket, put the original ROM chip back in and the game works fine. Removed the original ROM chip, inserted EPROM, still just a solid color screen. I even tried it on two different systems (AV Famicom and my toaster NES that I modded to have a Famicom cart slot too).
I don't have any equipment to program EPROMs myself, so I had an online friend that's been doing repros for a while program the EPROM and mail it to me. He used a prepared and translated rom file provided by another repro-er who has done a Lagrange Point cart. My online friend also verified it works in an emulator and was ready to be written to an EPROM (header removed, whatever else is needed). He also verified the write to the EPROM was successful. Unfortunately, he did not have a Lagrange Point cart for him to foolproof test it. I also triple checked that I wasn't inserting the EPROM backwards.
Research: Lagrange Point uses one ROM chip (where a lot of NES/Famicom games use 2 with one being for CHR and another for PRG). The ROM chip used is 512kbyte/4Mbit. According to what I've found people saying, a 27C040 EPROM is the same size and is a pin for pin replacement.
Direct sources:
http://krikzz.com/forum/index.php?topic ... 2#msg23652
http://krikzz.com/forum/index.php?topic ... 7#msg23907
At this point I'm pretty baffled as to what the issue is. I'm doubting my online friend botched writing the correct file/data to the EPROM since he's a very technical person and has done hundreds of repros, but at the same time the only issue I have is when I insert the EPROM into the cart. Is there possibly contradicting evidence that a 27C040 EPROM is not pin for pin compatible as stated in the external forum posts? Any suggestions are welcome.
So, a handful of months back the fan translation for Lagrange Point on Famicom was completed, but due to the special chip/mapper in the cart it is not currently compatible with any NES/Famicom flashcarts.
I've seen some people taking the "repro" approach of taking the original cart and replacing the original ROM chip with an EPROM that has the translated rom file programmed on it so it can be played on original hardware.
I'll start with the issue the give details on my research/troubleshooting to see if anybody has ideas.
Issue: When the EPROM is installed in the cart, the system just boots to a solid color screen (the same as if no cart is inserted).
Troubleshooting: Desoldered the ERPOM after things weren't working, installed a precision socket, put the original ROM chip back in and the game works fine. Removed the original ROM chip, inserted EPROM, still just a solid color screen. I even tried it on two different systems (AV Famicom and my toaster NES that I modded to have a Famicom cart slot too).
I don't have any equipment to program EPROMs myself, so I had an online friend that's been doing repros for a while program the EPROM and mail it to me. He used a prepared and translated rom file provided by another repro-er who has done a Lagrange Point cart. My online friend also verified it works in an emulator and was ready to be written to an EPROM (header removed, whatever else is needed). He also verified the write to the EPROM was successful. Unfortunately, he did not have a Lagrange Point cart for him to foolproof test it. I also triple checked that I wasn't inserting the EPROM backwards.
Research: Lagrange Point uses one ROM chip (where a lot of NES/Famicom games use 2 with one being for CHR and another for PRG). The ROM chip used is 512kbyte/4Mbit. According to what I've found people saying, a 27C040 EPROM is the same size and is a pin for pin replacement.
Direct sources:
http://krikzz.com/forum/index.php?topic ... 2#msg23652
http://krikzz.com/forum/index.php?topic ... 7#msg23907
At this point I'm pretty baffled as to what the issue is. I'm doubting my online friend botched writing the correct file/data to the EPROM since he's a very technical person and has done hundreds of repros, but at the same time the only issue I have is when I insert the EPROM into the cart. Is there possibly contradicting evidence that a 27C040 EPROM is not pin for pin compatible as stated in the external forum posts? Any suggestions are welcome.