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David Cook replied to the thread I broke and fixed Macintosh Portable (backlight). Attached backlight circuit schematic that I reverse engineered.Here are the IDs (see U13H): Backlit portable: $A5 10100101 Upgraded original portable: $A3 10100011 PowerBook 100: $AD 10101101 -
David Cook replied to the thread I broke and fixed Macintosh Portable (backlight). Attached backlight circuit schematic that I reverse engineered.They're outputs, so they could just be floating. Thanks for letting me know. If I get a chance, I'll also take a look. It wouldn't...
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AAppleTree replied to the thread I broke and fixed Macintosh Portable (backlight). Attached backlight circuit schematic that I reverse engineered.I wasn't sure where 74AC374's O0 to O4 (5 unused bits you referred to) were connected to. Traces from those pins went under 74AC374 and...
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David Cook replied to the thread I broke and fixed Macintosh Portable (backlight). Attached backlight circuit schematic that I reverse engineered.I had no idea that the "backlight id" and "backlight brightness register" were implemented in such a rudimentary manner. There are 5...
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David Cook replied to the thread I broke and fixed Macintosh Portable (backlight). Attached backlight circuit schematic that I reverse engineered.Incredible write up! It explains so much. Based on your schematic, the digital potentiometer chip (U14G) is actually being used as a...
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AAppleTree replied to the thread I broke and fixed Macintosh Portable (backlight). Attached backlight circuit schematic that I reverse engineered.Thank you for the warm welcome. I enjoy watching your videos. In fact, your video on the Portable backlight model taught me how to...
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Trash80toG4 replied to the thread Radius Full Page Display for Macintosh 512ke/Plus - Cloning project possibilities?. -
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About two years ago, I grabbed a second TRS-80 Model III, but this one has 48K and both of the 5.25" drives, so a lot more feature rich...
