How a 555 timer broke early C64 boards

The early Commodore 64 326298 boards have a flaw that prevents cartridges from using the reset line, which causes problems with the Final Cartridge, EasyFlash, Fung Fu Flash, and BackBit among others. I’ll show you how the 555 timer reset circuit works, why it causes the problem, and a simple mod to fix it.

Links
https://www.lemon64.com/forum/viewtop...
https://www.lemon64.com/forum/viewtop...
https://hobbytronics.home.blog/2023/0...
   • Commodore 64 Rev.A 326298 hardware mo...  

Chapters
00:00 - Intro
00:25 - The schematic is wrong!
02:58 - How the 555 timer works
05:27 - Looking at signals before
06:55 - How to do the mod
08:03 - Looking at signals after
10:34 - Outro