Tron boards not booting Bally MCR

tec9

Active member
Joined
Dec 25, 2006
Messages
2,111
Reaction score
23
Location
New Britain, Pennsylvania
Hey all-
I've finally gotten around to putting together a MCR test fixture. I threw this together because I have a small stash of MCR boards I'd like to get running! Here is what I'm working on now:
"Super CPU" with Tron ROMS- This is the middle PCB in a MCR stack. I have it connected to a known working Video Generator PCB. I can't get this to boot! Here is more details:
Known good-
Power supply/voltages- Running a switching power supply with a MCR PS adaptor
Video Generator PCB
Ribbon Cables
All socketed IC's verifed and sockets look good

Any ideas on what I should be looking at next? I have a logic probe, but not sure where I should be looking.
Thanks-
Mark
 
You say you have it setup on a test rig... what's the VBatt connected to?
If you don't have it connected on the harness you'll want to connect it to +5v.
 
Hi-
Thanks for the reply....I do have the VBATT connected to 5volts. Known working boardsets do boot up on the test rig, so I'm pretty sure that is good. Any other suggestions?
Thanks-
Mark
 
Check the reset pin of the Z80 on the super CPU board. If it's pulsing then the watchdog is barking. I don't have the schematics in front of me so I'l not sure if all the resets are driven by one global one on the Super CPU board or not... probably though.

If the watchdog is barking then it's most likely an addressing issue with the program ROMs or RAM.
 
Check the reset pin of the Z80 on the super CPU board. If it's pulsing then the watchdog is barking. I don't have the schematics in front of me so I'l not sure if all the resets are driven by one global one on the Super CPU board or not... probably though.

If the watchdog is barking then it's most likely an addressing issue with the program ROMs or RAM.



All of the RAM and ROM's have been replaced with known working ones.....I'll try and check the reset line with a logic probe, and see if it's pulsing. It should pulse once on powerup...right? The ribbon connectors are on the PCB's correctly, I've checked them with a meter.
-Mark
 
Back
Top Bottom