Tunnel Vision On Monochrome Active Matrix Powerbooks

[CC_333]

Reading this thread from the beginning (way back in 2013!), I've come to the conclusion that I don't want to have any PowerBooks with monochrome or grayscale active matrix displays. Too much trouble!!

However, the Portable, despite also having a monochrome active matrix LCD, doesn't seem to be affected. Has anyone ever figured out why?

c

 

[techknight]

Reading this thread from the beginning (way back in 2013!), I've come to the conclusion that I don't want to have any PowerBooks with monochrome or grayscale active matrix displays. Too much trouble!!

However, the Portable, despite also having a monochrome active matrix LCD, doesn't seem to be affected. Has anyone ever figured out why?

c

it is affected .I have one.

I just use it as a test display now.

 

[aplmak]

I have to add some recent observations of mine. I noticed with a Powerbook Duo 250 with an active matrix screen it had leaky caps of course. I replaced the caps. Now when the tunnel vision occurs it gets more darker around the bottom left where the leaky caps were that match up when the powerbook screen was closed. So it sat for years in a closed position while those caps leaked.... so the idea of moisture and electrolyte vapor getting inside the lcd really does seem to be the cause. I can completely see that the electrolytic vapors breaking down possibly the seal on the lcd display. This laptop was in a carry case and sat there I am sure for years while those caps leaked. It just appears to me a highly probably cause. I tried to remove the display to bake it but on the Duo 250 there are a lot of rubber bumpers in the display that are very difficult to deal with. One strip on the bottom of the LCD just did not want to come free from the metal frame. And of course I didn't want to bake it with the rubber strips. I gave up and reassembled it. I'm thinking maybe if I got a food dehydrator if that might work??? Just a thought!!!

 

[3lectr1cPPC]

Some months back we had a large industrial dehumidifier in the house, so I figured that I might as well stick the TV-affected PowerBook 540 in front of it since I had the opportunity. Didn't help at all, not really surprised.

 

[Shaddam IV]

I am currently "baking" a Powerbook 540 screen that has bad tunnel vision syndrome (starts at about 2 minutes after the machine has been tuned on; after 10 minutes or so, only the center area of the screen is lit, the outside is completely dark). I'm trying to de-humidify the screen by treating it as I would prepare apple chips: Very low temperature (160 F, or around 72°C) for around 20-24 (or even more) hours. I started yesterday evening and will stop tonight (or, to be on the safe side, tomorrow morning). I hope to be able to reassemble the machine on Friday and will report results here.

 

[Shaddam IV]

still baking

 

[croissantking]

Will be interested to see your results. I found that the higher temps everyone else has been successful with have damaged my front polarising film.

 

[Shaddam IV]

That‘s what I was thinking of. Thus treat the display like fruit chips… fingers x‘ed

 

[Shaddam IV]

So this is the LCD after 2.5 days at 159F in the oven. There is definite improvement (which really surprised me) in the corners: No tunnel effect in the corners at all (and it was really bad, totally black - for example, the Apple symbol in the menu bar was completely indiscernible. But the drying has apparently not gone beyond the first inch or so. So I'll continue drying the screen, this time for maybe a week or so.

 

[Shaddam IV]

I've decided not to put the LCD back in the oven for what should probably be 7+ days. Instead I'm buying an Infrared lamp and will try heating the screen that way.

 

[croissantking]

Oh how comes

 

[Shaddam IV]

Oh how comes

I don't want to blockade my poor oven for so many days on end - I'm planning to bake a cake (and possibly spare ribs) over the week-end... I'll use a thermometer on the display.

 

[croissantking]

I don't want to blockade my poor oven for so many days on end - I'm planning to bake a cake (and possibly spare ribs) over the week-end... I'll use a thermometer on the display.

You make me laugh

 

[Shaddam IV]

OK I'll post my setup once the lamp arrives and is in action. That'll likely make you laugh even more :-D

 

[croissantking]

Do it

 

[Shaddam IV]

Do it

It's toasting now. I'm doing the left side first, this is where the worst tunneling is taking place.

 

[croissantking]

It's toasting now. I'm doing the left side first, this is where the worst tunneling is taking place.

Careful with that screen bezel 🫣

 

[Shaddam IV]

Strangely, the screen gets hotter than the bezel. The IR lamp is a 100 W lamp - it's not all that hot. I can still touch the screen (briefly).

 

[luRaichu]

what if you put the LCD inside a food dehydrator (edit: nvm, somebody mentioned that already)

 

[Shaddam IV]

what if you put the LCD inside a food dehydrator (edit: nvm, somebody mentioned that already)

Not sure that the desiccator is hot enough to really get the water out. I‘ll continue toasting tomorrow.