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PowerBook 540c screen issue
Posted by: alectrona6400 on 2024-04-18 07:28:30
yeah so its likely active matrix, my bad. that cable on ebay unfortunately won't work.
Posted by: crazyben on 2024-04-18 08:10:44
I just confirmed that mine has Toshiba screen and the display cable part number is 821-0056-A 632-0050-A.
Posted by: 3lectr1cPPC on 2024-04-18 10:52:32
Caps are ruled out then. It's either the panel itself or a connection somewhere.
Posted by: jmacz on 2024-04-18 14:42:41
Note the ribbon cables sometimes visually look ok when they aren’t. Won’t know until you beep out each pin on both ends with a multimeter. I have found two that looked perfect but had an issue. I am referring to all three ribbon cables. If the cables an issue, you can find a replacement or do what I did and graft over the dead spot (if you see it) or use a flexible bodge wire from end to end.
Posted by: crazyben on 2024-04-20 14:10:54
I bought another 540c that has vinegar syndrome. I will replace the cable to see if that fixes it.
Posted by: 3lectr1cPPC on 2024-04-20 14:11:42
Did you verify that it also had the Toshiba display in it? If it isn't that panel than it won't swap.
Posted by: crazyben on 2024-04-20 14:13:15
Oh shoot didn’t think of that. fingers crossed 🤞
Posted by: 3lectr1cPPC on 2024-04-20 14:14:25
Would you be able to link the auction or post a photo from it showing the screen? Depending on how good the photos are, I can ID whether it's a Toshiba or a Sharp. The Sharp has a glossier appearance.
Posted by: crazyben on 2024-04-20 14:15:46
Here it is.
www.ebay.com

Vintage Apple Powerbook 540C Laptop Computer With Case - For Parts Or Repair | eBay

<p dir="ltr" style="margin-top:0; margin-bottom:0;">PLEASE CHECK PICS CLOSELY THIS HAS POWER CORD CANT GET IT TO COME ON. PLEASE CHECK SCREEN. NOT SURE HOW TO FIX. </p>
www.ebay.com
Posted by: 3lectr1cPPC on 2024-04-20 14:18:01
I'm pretty sure that isn't a Sharp. There's a small, small chance that it's the rare Hosiden panel, but it's probably a Toshiba.
Posted by: crazyben on 2024-04-20 14:19:44
I'm pretty sure that isn't a Sharp. There's a small, small chance that it's the rare Hosiden panel, but it's probably a Toshiba.
Awesome. Thank you for checking.
Posted by: MikeatOSX on 2024-04-23 14:54:44
I have a similar problem when I started one of my PB 540c today after 2 years:
The upper half of the screen is disturbed by vertical stripes.
Any hints please?
Posted by: 3lectr1cPPC on 2024-04-23 16:02:55
Cable or screen issue. Try reseating everything inside, they’re pretty prone to connection issues.
Posted by: MikeatOSX on 2024-04-23 22:54:28
Thanks! I hope it's not the screen inside.
Posted by: MikeatOSX on 2024-04-24 01:46:58
Cable or screen issue. Try reseating everything inside, they’re pretty prone to connection issues.
I have similar issues with my only PB 180c now. So the next days/weeks are reserved for these PBs and some more. :-(
Posted by: crazyben on 2024-04-25 11:34:45
I'm pretty sure that isn't a Sharp. There's a small, small chance that it's the rare Hosiden panel, but it's probably a Toshiba.
Yes is sharp.

Here is the update on this. I removed the vinegar syndrome display and plugged to display with missing line and it works. The display is as sharp (no pun indented) as it can be. The flickering issue is also gone. So i think the problem is with the display connector from logic board to the display.

Now i have one fully working 540c and one working headless 540c.
Posted by: 3lectr1cPPC on 2024-04-25 11:53:30
Yes is sharp.

Here is the update on this. I removed the vinegar syndrome display and plugged to display with missing line and it works. The display is as sharp (no pun indented) as it can be. The flickering issue is also gone. So i think the problem is with the display connector from logic board to the display.

Now i have one fully working 540c and one working headless 540c.
Rats. I guess my ID skills aren’t as good as I thought they were! I’m glad you got it sorted regardless - I’d try reseating that LB to display cable if you haven’t already, there’s a chance it’s loose at the logic board side. Either that, or it’s just damaged.
Posted by: crazyben on 2024-04-27 06:56:29
Rats. I guess my ID skills aren’t as good as I thought they were! I’m glad you got it sorted regardless - I’d try reseating that LB to display cable if you haven’t already, there’s a chance it’s loose at the logic board side. Either that, or it’s just damaged.
Hahaha yup. Now don’t go to Vegas to play blackjack lol. They use cards from same deck 🤣

I only have one working screen so I will keep the other headless.
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