AEChadwick
Well-known member
A friend gifted me a dead PowerBook 100. It was only mostly dead; all it took was replacing every capacitor, now it works fine.
The screen is predictably dim. As part of the repair, i took the LCD apart: the little CCFL has plenty of crusty black inside its ends, i’m sure it doesn't have much time left.
The 100 is wonderfully hackable, not least of all because you can read the schematics. Can it support replacing the power-hogging CCFL with a modern LED backlight strip? I spent a couple days poking around.
i checked each pin of the interconnect cable to try and unite it with the schematic and the interconnect board.
J12_pin6 is +5v/0v, it turns off when the powerbook sleeps. Perfect for ENA.
J13_pin3 is CCFL_PWR, 7.5v almost directly from the power jack. the LED board requires 9v-30v and prefers 12v, so i used a small boost board i had handy.
J13_pin2 is brightness: it hovers around 3v. However, mine might be broken: turning it does not seem to change the brightness of the CCFL, nor does it affect the LED strip in any way. So, full power all the time for now.
So far, this works, with a couple caveats: sometimes, selecting sleep does nothing, it simply refuses to sleep; sometimes, selecting shutdown results in a hang--not a freeze, you can move the wait-watch around the screen, it just never shuts down.
maybe I need to isolate the ENA line with a diode? maybe it's getting some bad feedback? I really am an idiot with electronics: i only actually know enough to make problems. Please post any ideas or concerns.
Next, i will pull the LCD back apart to see how it looks against the LED.
The screen is predictably dim. As part of the repair, i took the LCD apart: the little CCFL has plenty of crusty black inside its ends, i’m sure it doesn't have much time left.
The 100 is wonderfully hackable, not least of all because you can read the schematics. Can it support replacing the power-hogging CCFL with a modern LED backlight strip? I spent a couple days poking around.
i checked each pin of the interconnect cable to try and unite it with the schematic and the interconnect board.
J12_pin6 is +5v/0v, it turns off when the powerbook sleeps. Perfect for ENA.
J13_pin3 is CCFL_PWR, 7.5v almost directly from the power jack. the LED board requires 9v-30v and prefers 12v, so i used a small boost board i had handy.
J13_pin2 is brightness: it hovers around 3v. However, mine might be broken: turning it does not seem to change the brightness of the CCFL, nor does it affect the LED strip in any way. So, full power all the time for now.
So far, this works, with a couple caveats: sometimes, selecting sleep does nothing, it simply refuses to sleep; sometimes, selecting shutdown results in a hang--not a freeze, you can move the wait-watch around the screen, it just never shuts down.
maybe I need to isolate the ENA line with a diode? maybe it's getting some bad feedback? I really am an idiot with electronics: i only actually know enough to make problems. Please post any ideas or concerns.
Next, i will pull the LCD back apart to see how it looks against the LED.