bagheera369
Champion
Figured I could start in on some of the interesting repairs I wind up involved in at my shop, and hopefully they help someone out!!
2/7/19 - Nba Jam Cabinet - "New Cabinet" from some cheap raspi arcade emulator dealers....cant route the Raspi, so we put in an original Jam board,with a gonbes cga>VGA, and new power supply. Game kept freezing at UJ7. Three different Jam boards, all the same problem. Boards all work on test rig. Found three issues.
One, board was not getting enough voltage. Folks working on it didn't realize how power hungry Midway boards are, so now running steady at 5.35 volts at connector.
Two, couldn't run the Gonbes at 5.35v, so a second, small power supply was added to power just the Gonbes.
Three, even though the board was booting properly, the screen was still freezing at the UJ7 rom....turns out this was a setting in the Gonbes. Midway games require the VERT POSITION setting to be at 28 or higher. Any lower than that, and the screen freezes continuously. Something to do with the slower Hz refresh rate, and the Gonbes. Found answers online for this one.
Now game and screen running stable, and its off to its new home in Chicago.
2/7/19 - Nba Jam Cabinet - "New Cabinet" from some cheap raspi arcade emulator dealers....cant route the Raspi, so we put in an original Jam board,with a gonbes cga>VGA, and new power supply. Game kept freezing at UJ7. Three different Jam boards, all the same problem. Boards all work on test rig. Found three issues.
One, board was not getting enough voltage. Folks working on it didn't realize how power hungry Midway boards are, so now running steady at 5.35 volts at connector.
Two, couldn't run the Gonbes at 5.35v, so a second, small power supply was added to power just the Gonbes.
Three, even though the board was booting properly, the screen was still freezing at the UJ7 rom....turns out this was a setting in the Gonbes. Midway games require the VERT POSITION setting to be at 28 or higher. Any lower than that, and the screen freezes continuously. Something to do with the slower Hz refresh rate, and the Gonbes. Found answers online for this one.
Now game and screen running stable, and its off to its new home in Chicago.