Hello,
Having a very strange issue with a VA0.8 US Sega Saturn that I've been trying to put a region free BIOS into.
I'm using AM27C400-150DC chips but have found that for some inexplicable reason, the system will only boot if there is light hitting the window of the BIOS EPROM. This means that if I put anything over the window (piece of electrical tape, the rf shield etc.) it will not boot correctly. However if the window is not covered and is being hit by light then it boots up just fine and I was able to play my copies of Nights (JP) and Daytona USA (US).
At first I thought it was a weird chip defect but even after ordering several more I am still having this exact same issue. A region free BIOS is kind of useless if I can't actually close the system back up.
Does anyone have any idea what's wrong? Do I just need to source a completely different chip because by some freak accident I found the only condition that this model works in?
Edit:
I did verify all 40 pin point connections and the system has zero issues when I reinsert the original BIOS chip
Having a very strange issue with a VA0.8 US Sega Saturn that I've been trying to put a region free BIOS into.
I'm using AM27C400-150DC chips but have found that for some inexplicable reason, the system will only boot if there is light hitting the window of the BIOS EPROM. This means that if I put anything over the window (piece of electrical tape, the rf shield etc.) it will not boot correctly. However if the window is not covered and is being hit by light then it boots up just fine and I was able to play my copies of Nights (JP) and Daytona USA (US).
At first I thought it was a weird chip defect but even after ordering several more I am still having this exact same issue. A region free BIOS is kind of useless if I can't actually close the system back up.
Does anyone have any idea what's wrong? Do I just need to source a completely different chip because by some freak accident I found the only condition that this model works in?
Edit:
I did verify all 40 pin point connections and the system has zero issues when I reinsert the original BIOS chip