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what causes LCD rot?

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For lack of better term, I've had a Duo 230 suffer from small pink blob and I've seen a few other like this. For some reason it seems I've seen this only in Powerbook B&W LCD?  Maybe I hadn't seen it elsewhere because non-Mac laptops were often thrown in the trash before it gets old enough to suffer from the rot.

 

It looks like there's some kind of parasite inside LCD eating away the inside, leaving pink trail behind. I'm pretty sure it's not pressure mark or cracks as they normally wouldn't form irregular spiderweb like damage.

 

bad_lcd_zps06ab6f6e.jpg

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It's some sort of mould/fungal bloom I reckon - I don't think it can be cleaned off either by separating the sublayers of the LCD, but you could try.  Seems more common on passive LCDs - like uni I've only ever come across it on a couple of PB100s.

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That is damage from a micro fissure and the LCD liquid leaking out into the in-between layers of glass in the display panel by capillary action. It is caused by impact damage hitting the screen at the middle of the largest blob. The damage itself was not apparent at first as was not big enough to leak out immediately but when the display was shut down and closed up, the liquid started to spread out from the micro-fissure. It is a very slow process that looks like the LCD is rotting away.

 

I have seen this on many LCD display systems on Macs, PCs, Palm Pilots, Watches and a few calculators. Even one of my Yaseu hand-held radios had this happen to it.

Edited by Elfen

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The Powerbook 1xx series has a few models that are very prone to this particular issue and it seems to be as Elfen and Uni say, either a weak spot when it was made that finally gave way due to age and use, or a small trauma to the screen that with age finally caused the scree to give, but either way, you have a screen that is not repairable. For some it seems to continue to spread (just a guess but I would imagine it has to do with the magnitude of the defect/damage that precipitated the problem), but for some it seems to stay contained. It's very difficult to predict which path it will take for a given screen. It's more of a wait/see situation. Your only hope is to replace the screen.

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I noticed this on my duo 230 a few days ago, as well. Almost center of the screen.

That really sucks, PintoDave. Something hit the screen at the center of the blob.

 

Or in one of my PBs (an iBook G3), I closed the screen, forgetting that there was a small case screw from another repair job on the keyboard. It was enough to wreck the screen. The screens for newer G3/G4 PB's & iB's are easy to get. Harder for the older PBs and Duos.

 

I need a screen for a 280, either in B/W/Grey Scale or Color myself. Preferably in B/W/Grey Scale since I already have a 280c and the one in need of a screen is B/W/Grey Scale - it completes the collection. Only ones missing to complete is a 260 & 270.

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That really sucks, PintoDave. Something hit the screen at the center of the blob.

 

Or in one of my PBs (an iBook G3), I closed the screen, forgetting that there was a small case screw from another repair job on the keyboard. It was enough to wreck the screen. The screens for newer G3/G4 PB's & iB's are easy to get. Harder for the older PBs and Duos.

 

I need a screen for a 280, either in B/W/Grey Scale or Color myself. Preferably in B/W/Grey Scale since I already have a 280c and the one in need of a screen is B/W/Grey Scale - it completes the collection. Only ones missing to complete is a 260 & 270.

 

260? What spec is that?  I only knew of 210, 230, 250, 270, and 280 plus the 2300.

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The Duo 220's, 240's and 260's are the rarest of the Duos out there! They use the former inviso "clear" cases, making them invisible!

lol - yeah, its a typo.

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My 230 was in a box in storage for the longest time, I'm assuming I must have placed a heavy box on top of it at some point in time and messed it all up. That's what I get for being sloppy with my computer storage in the past. :( I'm much more careful with things now!

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You're as guilty as I in the storage issues. The problem lies in that the keyboard of the Duos does rub up against the screens, as in a few Powerbooks. More so when the rubber pads on the screen that contact the rest of the PB wears down flat.

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I’m having this issue of “lcd rot” in many systems. Symptoms vary - from cracked panels to fungi-like patterns

first it was a Digital HiNote 486 laptop - it was carefully stored in a horizontal shelf without any other weight on top - the screen cracked al liquid cristals came pouring out.

Some compaq LTEs are also turning up with strange patterns. They have had no physical stress placed upon, but all of the sudden the lcds start to rot.

Two PowerBook 160 have also developed cracks and air bubbles within the lcd layers.

This is a serious concern to those that collect and enjoy having these old machines in working condition..

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It’s the adhesive on the polarizing film rotting. I think all of us laptop collectors sooner or later are going to start having to learn how to replace the polarizing film. I’ve actually got an LCD with this problem (it had it when I received it) that I had been a playing with trying to replace the film on it. Haven’t messed with it in quite a while though. But I do still have it, so I’ll dig it back out one of these days.

 

What you are seeing that looks like cracks is likely just the old adhesive. It sometimes shrinks and produces a “cracked” looking pattern. The LCD is likely fine underneath that mess of old, rotten adhesive. I found that acetone does a pretty decent job of softening the glue, and then you can scrape it off.

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EDIT 1: Thanks, PB145B!  :)

 

Good news everyone!

 
So I had this damaged PowerBook 160 LCD lying around and decided to investigate following PB145B suggestion.
 
I removed it from the reflector bed and looking at its transparency, the outlook was even worse than previously thought.
 
Apart from the apparent surface crack and bubbles lying around, I could see cracks on the glass itself.
 
Having nothing to lose on this unit I started to peel off the polarizing film.
 
I must warn you, the adhesive smell is pretty intense.
 
As I scraped the adhesive from the glass - using a flat blade and alcohol, It became apparent that the LCD itself was fine, every apparent damage was related to the adhesive (bubbles and the apparently broken glass) and the polarizing film (surface crack and apparent leak).
 
Now I must find a way of getting a new polarizing film and adhesive...
 
EDIT 2: I noticed some polarizing films come with self-adhesive and there are mentions to several polarizing angles - does anyone know what angle to order for a PB160? and if I should opt for one with self-adhesive? Thanks!
 
Initial aspect of broken PowerBook 160 LCD
 
Polarizing film
 
 
Aspect of adhesive over LCD glass
 
Flat blade and adhesive peeled off
 
Cleaned LCD
 
Cleaned LCD
Edited by goncalo

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3 hours ago, goncalo said:

Thanks, PB145B!  :)

No problem. Glad I could help :) 

 

You did a great job at cleaning that LCD up! As far as the polarizing film goes, I have no clue. Hopefully someone else will chime in that knows more.

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You can purchase it online. youll need to get multiple samples and figure which ones work the best. Once the old stuff is off, you can lay the new stuff on behind, and in front. just lay it on there. Eyeball it. check contrast, brightness, etc..

 

Once you find the best one, then stick with it ;-)

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In a pinch, if the old polarizing film is still intact and in *okay* (meaning not great, but usable) condition, could it be reused with new adhesive?

 

Of course, new film is ideal, but I'm curious if the old film, given the proper conditions, is still viable.

 

Also, could it be advantageous to preemptively replace the film on certain at-risk LCDs (in general, those stored in hot, humid environments would seem to be particularly prone to adhesive rot, if I'm interpreting this thread properly) to prevent this kind of thing from occurring in the first place?

 

c

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How would you apply new adhesive without imperfections/bubbles? 

 

Then you would need sheet adhesive that bonds clear. 

Edited by techknight

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I'm glad this issue has been definitively solved. I've had this happen to several screens, and never been completely sure of the cause since I've had poor luck getting the polarizer separated without damaged the underlying screen.

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I would say it's far from definitively solved?  Unless we can find a cheap substitute replacement polariser film, LCDs will continue to degrade over time.

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I've bought a "Polarizer Film Angle Tester" from aliexpress (~10€) - I'm hoping it will help me solve the angle question regarding this PowerBook and many other screens.

But alas, this project is on hold right now - this retrocomputing stuff is a slow process for me ;-)

As for prices, I've found that a 17" sheet is about 10€. But I've recently noticed they are getting more expensive..

 

Edited by goncalo

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