Sep 152014
 

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.