• Updated 2023-07-12: Hello, Guest! Welcome back, and be sure to check out this follow-up post about our outage a week or so ago.

PowerBook 100 Replace CCFL with LED (in process)

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.
 

Attachments

  • IMG_4207.jpeg
    IMG_4207.jpeg
    3.3 MB · Views: 63
  • IMG_4208.jpeg
    IMG_4208.jpeg
    4.2 MB · Views: 55
  • Display Cable.png
    Display Cable.png
    522.1 KB · Views: 51
  • PB100_interconnect board_noted.pdf
    373.8 KB · Views: 4
  • PB100_interconnect board_noted.jpg
    PB100_interconnect board_noted.jpg
    1.1 MB · Views: 69
  • IMG_4206.MOV
    20.6 MB

desertrout

Well-known member
Hot damn! Thanks for posting on this. Inspiring me to try this on a different 1xx PB (my 170 and 180 both have dim ccfl's)

Also - thanks for posting to schematic... didn't realize it was available!
 

AEChadwick

Well-known member
Hot damn! Thanks for posting on this. Inspiring me to try this on a different 1xx PB (my 170 and 180 both have dim ccfl's)
i would love a solution for other 100-series machines, i have a PowerBook 180 that i adore. But the 100-series screen controllers are quite different, and i cannot find any schematic to provide insight. (I was encouraged by how simple the PowerBook 100 boards were: so minimal, i figured i might have a chance of understanding them.)
 

desertrout

Well-known member
But the 100-series screen controllers are quite different, and i cannot find any schematic to provide insight. (I was encouraged by how simple the PowerBook 100 boards were: so minimal, i figured i might have a chance of understanding them.)
True true. The 140 schematic on bitsavers doesn't seem to include anything beyond than the mother and daughter boards (will look closer)... Still, should be doable (says me, the guy who is knows just enough to be dangerous).
 

AEChadwick

Well-known member
i printed a mock-CCFL tube with a 2mm groove to hold the LED strip in place.

i also made a little "tray" to replace the inverter board. (I sawed the connected off the LED controller and squeezed it in.)

I wish the picture communicated how glorious this looks.

Except: my attempts to clean the LCDs connectors have only revealed more flaws (... maybe i can source a replacement LCD.

(For real, i have a Macintosh Portable that i will trade for PowerBook 100 parts...)
 

Attachments

  • PB100_InverterInsert-stl.zip
    5.3 KB · Views: 1
  • PB100_CCFLinsert-stl.zip
    3.7 KB · Views: 1
  • IMG_4212.jpg
    IMG_4212.jpg
    3 MB · Views: 56
  • IMG_4218.jpeg
    IMG_4218.jpeg
    3 MB · Views: 69
  • IMG_4219.jpeg
    IMG_4219.jpeg
    2.6 MB · Views: 70

alexGS

Well-known member
Except: my attempts to clean the LCDs connectors have only revealed more flaws (... maybe i can source a replacement LCD.
Ahh yes, I have a Powerbook 100 LCD where the brown ribbons (with their driver chips) have disintegrated, mainly as a result of the capacitor juice leaked from the 8x rectangular electrolytics on the back :(

I have another LCD where the ribbons are intact but there’s a pink splodge from the trackball damage.

I was wondering if it’s possible to transfer the ribbons from one LCD to another, i.e. peel them off the glass and rebond to another.

Anyway in the meantime, thank you for sharing the STL for the LED strip mounting :) I shall download that onto my PC. I do have those LED backlight kits but I’m worried that the contrast control is integrated into the inverter board’s function - how have you replaced that? My 100 always needs a tweak of the contrast as the display warms up
 

AEChadwick

Well-known member
I do have those LED backlight kits but I’m worried that the contrast control is integrated into the inverter board’s function - how have you replaced that? My 100 always needs a tweak of the contrast as the display warms up

the contrast control is independent of the inverter board, and still works great--if anything, it seems more responsive under the more powerful light. according to the block diagram, the contrast pot connects directly to the lcd via the interconnect board. (seriously, the simplicity of the 100 makes this hack possible... i wish the 1400 or the 500-series were as modular...)
 

Attachments

  • Powerbook 100 LCD power block diagram.png
    Powerbook 100 LCD power block diagram.png
    160.3 KB · Views: 54

AEChadwick

Well-known member
i traded parts with @360alaska to get an excellent screen; i transplanted my LED-CCFL replacement and got it all in place, and it’s gorgeous.

apparently i accurately rewired everything, because the brightness actually does work.

quick demo video attached (ignore that little freakout when i turn the contrast too far).

IRL this screen is as pretty as an SE/30, fight me.
 

Attachments

  • PB100.mov
    17.7 MB

AEChadwick

Well-known member
bonus, i was missing one foot, so i modeled a replacement. The PowerBook 100 feet are actually fantastic tiny machines, two parts in separate tracks that flex and expand to extend the feet. Standard disclaimer, "artist not engineer" and "please remix and share.”

I printed from PETG for strength (all i have right now is black). The original feet pop into place with little tabs; you pinch the tabs to remove the foot. I tried to achieve that, but kept breaking the tabs. my solution was to replace the snap-tabs with a couple M2.5 screws with wide flanges.
 

Attachments

  • PB100 Feet.png
    PB100 Feet.png
    203.1 KB · Views: 26
  • PB100_feet.zip
    86 KB · Views: 4
  • i_screwed_it-In.jpeg
    i_screwed_it-In.jpeg
    1.1 MB · Views: 27
  • revise_reprint_repeat.jpeg
    revise_reprint_repeat.jpeg
    1.6 MB · Views: 25
  • works.jpeg
    works.jpeg
    1.7 MB · Views: 27
  • PB100_foot_in-situ.jpeg
    PB100_foot_in-situ.jpeg
    1.6 MB · Views: 36

gcp

Well-known member
IRL this screen is as pretty as an SE/30, fight me.
Incredible... Makes me super nostalgic for Dad's PB 100 that he ordered immediately when they were announced... Loved that little machine. Picked up a 180c a while back to try to scratch the 68k PowerBook itch, but it's not the same! :D
 
Top