I have an issue with my Sunset Riders that has persisted since I got it. At the time I complained to the seller who assured me that the PCB was just super picky about the 5v supply. I didn't have a PSU with an adjustable 5v, so I just foolishly believed him (though it may have worked to him, so I can't say if he's being dishonest).
A few years later when I did get one in my Astro City, and was able to set it to precisely 5.00 at the board edge, it got pretty clear that it fixes nothing.
IIRC the listing showed a picture of the game running, but it's been many years. So it's possible that this issue happened in shipping. Though it's also a possibility that the seller was trying to pass on a broken pcb.
What I find really curious is that the board seems to be working. I get the correct character graphics, the ROM/RAM check is running, and all of them are tested OK, including the 5 socketed EPROMs which I had figured could be the cause (I'd assume the CPU is hitting invalid code and returning to the reset vector). Basically at the moment when the game is expected to display the copyright screen, it just resets instead.
I also tried resetting with the test button held (hoping I could get into the test menu somehow), re-initializing the security EPROM. Not that it was an issue anyway.
I really have no clue how to go on diagnosing this problem, on a board that otherwise seems to be working. Any clever ideas from the big forum brains?
A few years later when I did get one in my Astro City, and was able to set it to precisely 5.00 at the board edge, it got pretty clear that it fixes nothing.
IIRC the listing showed a picture of the game running, but it's been many years. So it's possible that this issue happened in shipping. Though it's also a possibility that the seller was trying to pass on a broken pcb.
What I find really curious is that the board seems to be working. I get the correct character graphics, the ROM/RAM check is running, and all of them are tested OK, including the 5 socketed EPROMs which I had figured could be the cause (I'd assume the CPU is hitting invalid code and returning to the reset vector). Basically at the moment when the game is expected to display the copyright screen, it just resets instead.
I also tried resetting with the test button held (hoping I could get into the test menu somehow), re-initializing the security EPROM. Not that it was an issue anyway.
I really have no clue how to go on diagnosing this problem, on a board that otherwise seems to be working. Any clever ideas from the big forum brains?