Apple IIe PAL Color Deep Dive and Repair

Support Noel's Retro Lab on Patreon:   / noelsretrolab   This Apple IIe wasn't outputting any color, so I started doing some testing until I convinced myself that there really was something wrong with it. This is a PAL machine (European) so the video-generating circuit is completely different than the NTSC. Or rather, it's added on top of the NTSC to simulate the color interference on NTSC devices. I go on a deep dive inside the PAL color-generating circuit trying to understand how exactly it works, and comparing our assumptions with real oscilloscope measurements. Until eventually... Understanding the Apple IIe by Jim Sather. An absolutely fantastic book that really helped me understand the ins and outs of the PAL circuit: https://archive.org/details/Understan... Good explanation of the NTSC interference and how to produce colors from the Apple II: https://www.xtof.info/blog/?p=768 Connect with Noel's Retro Lab: Discord ➤   / discord   Facebook ➤   / noelsretrolab   Twitter ➤   / noelsretrolab   Instagram ➤   / noelsretrolab