The end of a PB170 LCD? — #23

Post #23 by tomlee59

Source Forum	68kMLA
Category	Troubleshooting
Post Date	Sun, 15 May 2011 - 22:39
Original URL	https://68kmla.org/bb/threads/the-end-of-a-pb170-lcd.22190/

Post

Thank you. Hmmm. Well at the risk of derailing the thread, do you have any idea what causes darker areas around the edge of an LCD screen? I looked at the screen last night and it's not actually dark, it's just dimmer around the edges than in the middle. I've also seen LCDs that look like they have a bruised spot in the middle, where the image is slightly darker/dimmer than on the rest of the screen. I've never mananged to imagine what could cause such effect in LCDs.

From what I understand, the "progressively darkening corners" problem is due to poor edge seals, allowing moisture to contaminate the liquid crystal. This phenomenon first showed up in the active-matrix 1xx Powerbook series. Allegedly, the damage is somewhat reversible by doing a long, elevated-temperature bake inside a desiccated atmosphere. I've not had the patience to run a clean experiment to verify whether that method actually works.