Ristar ~ Sega Mega Drive Cartridge Repair ~
I picked up a cheap slightly tatty Ristar a few months ago but didn’t get around to testing it until yesterday and found that it refused to boot.
Upon opening up the cartridge you can see the cartridge connector pins are very dirty but cleaning them did not help at all and it still refused to boot.
Looking at the rear of the cartridge PCB you can see that there is some sort of moisture/corrosion damage to the solder and trying to re-flow the solder is not really an option as it crumbles when you apply any heat.
Since I am unsure if the Mask Rom still works and if the single capacitor was the culprit for the damage I remove both of them from the PCB:
I cleaned up the pins on the Mask Rom and to confirm it works I need to attempt to dump its contents.
Ristar uses a 42pin 16Mbit (2MB) Mask Rom which I found out is pin compatible with a M27C160 EPROM.
After setting my Top3000 Universal USB Programmer to M27C160 I read the Mask Rom contents and create a binary file dump which I then opened up in HxD:
However this binary file is unusable since Mega Drive ROM files are byte swapped and can not be compared to any known CRC from a good dump of the game.
After using BINman to byte swap my binary dump the binary file becomes much more readable:
So now I load up the KEGA Fusion Emulator to confirm it works and it does!
I now know for sure my Mask Rom is good, but for good measure I check my binary dumps CRC which is “6511aa61” and an exact match for the No Intro “Ristar (USA, Europe).md”
I now used solder wick to remove all the bad solder from my cartridge PCB and using contact cleaner I cleaned up the PCB as best as possible:
Using my Multimeter I checked for continuity between the traces from the cartridge connector pins and the Mask ROM via’s which thankfully were all good. I also tested the 47uf 16v capacitor which was testing good for capacitance but I decided to replace it with a new one I had on hand just in case:
After placing the Mask Rom and new Capacitor in place I re-soldered them back in:
Now time to test it again:
Another success! 