I’m pleased to have completed a repair on my second PCB – “Mikie – Highschool Graffiti”.
When I first got the PCB I powered it up and on boot up, I could hear the sounds of the game working, but only horizontal lines on the screen at different points:
https://www.youtube.com/watch?v=WnCiMWnpjvA
I found a broken 74LS373 @ A8 which corrected the screen so I could see the game, but the sprites and title screen were still corrupted:
https://www.youtube.com/watch?v=r0GRfbg_4cU
I found yet another broken 74LS373 @ C6. This mostly corrected the sprites but there was still issues with sprite selection:
https://www.youtube.com/watch?v=3eY6N_BLh9Q
….and lastly I found a problem 74LS153 @ A5 which corrected the sprite selection on the characters and title screen:
https://www.youtube.com/watch?v=7dZ8WQco_hk
Mikie PCB back from the dead!
I’ll add more detail to this repair at a later date.