PowerBook 100 screen recap

[Ron's Computer Videos]

I was reading this great article about recapping a PowerBook 100, and was curious if anyone else here had performed a similar repair... and what was the physical size of the tant caps you ended up using on the LCD?

Thank you!

Repair: Apple Macintosh PowerBook 100 “Gotta re-cap ’em all!”

In the last part of this little project, I managed to refurbish the two PowerBook 100 power supplies to a working condition. The next step is to refurbish the main unit itself. Even though I was eq…

goughlui.com

 

[Fizzbinn]

When I recapped my PowerBook 100 I used these for the LCD:

3.3µF - 35V - SMT - Size B - 581-TAJB335K035SNJ (Mouser P/N)

 

[Fizzbinn]

Alternatively you could use these too:
3.3µF - 35V - SMT - MLCC - 810-C3216X7R1V335M6A (Mouser P/N)

They are “Multilayer Ceramic Capacitors“ vs. the Tantalums above. I used them when I recapped my Duo 230 LCD, they‘re smaller, arguably fit better:

 

[Daniel Hansen]

Yeah this approach is just SO much smarter than trying to use radial electrolytics... which is what I did and it was silly. It works of course and looks more 'original' (as if that matters), but it felt like I was twisting myself into knots.

 

[Ron's Computer Videos]

Recapped my display, and it seemingly did not resolve the issue

 

[Daniel Hansen]

Recapped my display, and it seemingly did not resolve the issue

What's the issue you're experiencing?

 

[Elemenoh]

I recently recapped a Duo 230 LCD which also uses 3.3uF 35V caps. I also went with tiny ceramic caps (3.20mm x 1.60mm).

DigiKey link.

 

[Ron's Computer Videos]

What's the issue you're experiencing?

The display appears to "light up" but nothing is ever displayed.

 

[Fizzbinn]

The display appears to "light up" but nothing is ever displayed.

Glass half full: The florescent backlight is working!

Has the logic board been recapped? Getting a startup chime? HD
activity noises?

I guess you’ve double checked at the connections and played with brightness and contrast?

 

[Ron's Computer Videos]

Glass half full: The florescent backlight is working!

Has the logic board been recapped? Getting a startup chime? HD
activity noises?

I guess you’ve double checked at the connections and played with brightness and contrast?

Startup chime, yes!
HD activity sounds, yes!
Cleaned the pots for B&C. yes!

 

[Fizzbinn]

Startup chime, yes!
HD activity sounds, yes!
Cleaned the pots for B&C. yes!

Clearly, you have angered the PowerBook gods somehow and must use Windows Me exclusively for a week to atone.

….I got nothing

 

[Daniel Hansen]

A few things spring to mind:
- verify the display cable is good / properly connected
- possible there's an issue on the inverter board... there are two electrolytic caps on it that could be out of spec causing issues with brightness or contrast
- there's a chance that one of the inductors part of the boost converter has been affected by cap leakage, and is not supplying the required supply to the display... one or both of the 150uH's, located here:

 

[GiGaBiTe]

I second checking that area on the PB100. I had the exact same problem with no display and the problem didn't reveal itself until I flipped the board over and L3 fell off the board, it was hanging on by a thin wisp of a corroded leg.

All three inductors should be removed and closely inspected on the bottom, they tend to wick up the leaked electrolyte from the nearby caps, which corrodes the copper coil connections to the legs and sometimes corrodes the copper coils clean out of the body.

Also make sure you clean that area VERY thoroughly. the stupid leaked electrolyte can cause current paths between the nearby chips and cause erratic behavior. I had to wash the one I worked on 5 or 6 times to get it all off.

 

[caliban10]

I'm doing this exact repair & my L3 broke a leg as well while I was desoldering it. Appears to be pretty common.

What should I replace it with? I'm shopping for 150uH's but what Maximum DC Current do I need? Mouser has up to 50 A.

 

[GiGaBiTe]

I'm doing this exact repair & my L3 broke a leg as well while I was desoldering it. Appears to be pretty common.

What should I replace it with? I'm shopping for 150uH's but what Maximum DC Current do I need? Mouser has up to 50 A.

This is what I used to replace mine. Unfortunately though, it is out of stock until October.

https://www.mouser.com/ProductDetail/851-RCR875DNP-151K

I found a substitute that is the same dimensions with a slightly higher 720 mAh rating that will probably work:

https://www.mouser.com/ProductDetail/ABRACON/AISR-875-151L?qs=Y3s8Jkk9bu%252BYkJiucAXm5g%3D%3D

 

[caliban10]

Really appreciate the links. Very helpful.