68kMLA Classic Interface
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| Powerbook 100 display issue | |
Posted by: techknight on 2021-12-15 10:51:26I've seen this once and fixed it by replacing the full display, maybe its the cable or something? In this case it was not. like I said it was a failure in the logic board, it was not providing one of the required voltages for the display. | |
| Posted by: techknight on 2021-12-15 18:15:56 Right here:  one of the two 150uH inductors, the pin gets eaten away, and it fails. prevents that voltage from being generated. | |
| Posted by: 3lectr1cPPC on 2021-12-15 18:49:39 I can see how that failure wouldn't be easy to spot - thank you for your explanation! | |
| Posted by: Trash80toHP_Mini on 2021-12-16 06:42:02 What are the specific component designations? Hazarding a guess here, but figured everyone else who's not up to snuff on this stuff would like to know as well. Are the inductors good to go with a trace repair or should they be replaced along with the caps? On the dead pixel front: I just bought another 100 for backup parts from a member. Very happy with it, knew it had trackball damage, but the rubber on the lid appears to be intact. The spacing of lid to base is perfectly even front to back, so the rough handling hypothesis still stands for some 100s I think. Will the panels with that damage ever work again or are they gone for good? The screen was what I wanted to use for my test setup, go figure. | |
| Posted by: 3lectr1cPPC on 2021-12-16 07:34:23 The screen should still work with a recap, it will just not display anything on the damaged area. Sure, it will always have that defect but it could be a lot worse. | |
| Posted by: Cedsrepairs on 2021-12-29 03:24:18 I'm flattered to be quoted as a source of info for PB100 repairs 🙂 Indeed my own screen suffers the same problem, and it's trackball impact ( due to the long grey rubber stripes turning into goo, so less thick, and the ball that's never supposed to touch the screen now touches it) This especially happens during shipping (so if you buy a PB100 that looks neat, ask the seller to remove the trackball !) However, all plastics in PBx series are VERY brittle due to age; so it's likely removing the trackball will... break the pins of the trackball ring around it (been there). Choose your evil ! Yeah --- retro computing is full of frustration I think of selling all my collection twice a month. And then go on. 🙂 | |
Posted by: captjon320 on 2022-03-17 07:15:50I will have to get pics with the details, but here is the root cause: I’m working on one of these and after the recap, ultrasonic wash, bake and dry; I now get a backlit screen and nothing else. I would be gracious if you could point me in the correct direction to fix the voltage. I have included some pics of the area I believe you are talking about, but do not know where to go next. EDIT: sorry, just found your picture. Are these the two that likely need replacement? | |
| Posted by: techknight on 2022-03-17 08:14:03 No, they dont need replaced. they need removed and checked. to make sure they are still good and traces underneath are fine. All three of them btw | |
| Posted by: captjon320 on 2022-03-17 11:39:58 Perfect, thanks for the information. That will be my next check. | |
Posted by: captjon320 on 2022-03-17 15:21:15No, they dont need replaced. they need removed and checked. to make sure they are still good and traces underneath are fine. Update: removed all three and the traces look good on the board. The inductor from L3 (right in between all four caps) has the plastic molding broken off underneath, which holds the pins steady on the bottom. This may have been from my removing, but it’ll need to be replaced. I have included some pictures. Once I get away from capacitors, I'm way out of my league. From your previous picture I would guess this is one of the 150uH inductors? The ones I took off are not labeled. | |
| Posted by: captjon320 on 2022-03-18 09:05:27 Update: I checked the continuity of all three inductors and they are good, so I don't know where to go from here. Traces look good as well, I have posted some pictures from yesterday. If there is another area I should focus on trouble shooting, I'm open to ideas. | |
| Posted by: PotoMac on 2022-03-29 11:55:19 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. | |
| Posted by: Cedsrepairs on 2022-09-15 04:52:10 I just got a new PB100 today, of course it does not start and has leaky caps. So i'll recap a PB100 once again.🙂 I've been lookin for one since a long time, as I've got a perfectly working one (recapped, bluescsi, etc) but it had red dead pixels due to trackball impact This new PB100 I bought has a perfect screen, and is less yellowed... I'll probably update my previous topic, it's likely I'll chose the replacement caps (even) more carefully. | |
Posted by: imactheknife on 2022-10-14 16:26:11I just got a new PB100 today, of course it does not start and has leaky caps.Any update🙂 | |
| Posted by: Cedsrepairs on 2022-10-15 07:39:06 Do you believe me if I tell you that since posting this I have bought no less than two other vintage computers all needing repair Is there like an AA for vintage enthusiasts to share their problems buying useless junk ? 🙂 Joke apart the parts are in, this is my next next project. | |
Posted by: desertrout on 2022-10-15 08:53:47Is there like an AA for vintage enthusiasts to share their problems buying useless junk ? 🙂Let me know if this group exists and when the next meeting is please | |
| Posted by: imactheknife on 2022-10-15 18:04:13 Yea, will all need to go to these meetings and share our love err problems for old vintage stuff like macs | |
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