Hi all,
I've finally written up my two latest repair adventures over at my site, HonchoC64.com. Both are 1985 Capcom boards, and both were stubborn in their own way.
Ghost'n Goblins had an intermittent memory fault that only showed up when it felt like it. I ended up writing my own 6809 assembler test routines to corner it. The board now runs flawlessly on all-original hardware.
Interactive schematics: https://honchoc64.com/gng/
Repair story: https://honchoc64.com/gng-story.html
Commando was a bigger job: two defective boards planned to become one working borad, dealing with a dead CPU, a stopped clock, flaky ROMs and stuck flip-flops across the three-deck stack (around 250 chips). In the end I got both boards back in action, but it required a fair number of new ICs. Along the way I converted all 18 sheets of the original 1985 schematics into an interactive format, with IC-level walkthroughs of how each section of the machine actually works.
Interactive schematics: https://honchoc64.com/commando/
Repair story: https://honchoc64.com/commando-story.html
The interactive schematics are the part I'm most pleased with: clickable, navigable versions of the originals that let you explore at component level instead of squinting at scanned PDFs. Hope they're useful to anyone tackling these boards. Feedback and corrections very welcome!
/Honcho
I've finally written up my two latest repair adventures over at my site, HonchoC64.com. Both are 1985 Capcom boards, and both were stubborn in their own way.
Ghost'n Goblins had an intermittent memory fault that only showed up when it felt like it. I ended up writing my own 6809 assembler test routines to corner it. The board now runs flawlessly on all-original hardware.
Interactive schematics: https://honchoc64.com/gng/
Repair story: https://honchoc64.com/gng-story.html
Commando was a bigger job: two defective boards planned to become one working borad, dealing with a dead CPU, a stopped clock, flaky ROMs and stuck flip-flops across the three-deck stack (around 250 chips). In the end I got both boards back in action, but it required a fair number of new ICs. Along the way I converted all 18 sheets of the original 1985 schematics into an interactive format, with IC-level walkthroughs of how each section of the machine actually works.
Interactive schematics: https://honchoc64.com/commando/
Repair story: https://honchoc64.com/commando-story.html
The interactive schematics are the part I'm most pleased with: clickable, navigable versions of the originals that let you explore at component level instead of squinting at scanned PDFs. Hope they're useful to anyone tackling these boards. Feedback and corrections very welcome!
/Honcho
