New theory on the cause of the infamous Tunnel Vision problem - Testers needed!

[3lectr1cPPC]

I don’t believe my 540 does that, my non affected 170 definitely doesn’t.

 

[Paralel]

It sucks. I may revisit it at another time but for now I may buy one of the passive matrix models to avoid dealing with tunnel vision.

For the price I paid ($50) I can live with it.

Since you want to swap out the screen anyway, I would suggest trying to up the temperature slightly to see if that will provoke any improvement, 110 C?

If my vapor pressure of water theory is correct, and assuming the boiling water is following the gas law, PV=nRT, and for our situation, essentially PV=T. Also the volume of the water must remain constant due to volumetric constraint, then P=T. As the temperature increases, so does the pressure. If the pressure is higher, it's possible it could drive more water out of the screen. At a certain point it would no longer be possible to up the temperature since the components will be damaged, but until we reach that point, in cases of extreme TV, it may be worth attempting to increase the temperature incrementally.

For anyone wondering why the center cleared up and not the rest of it, It does support my vapor pressure theory involving water. Think of the water in the screen as a series of straws that are holding liquid, running from the edge to the center of the screen. As it is driven out of the monitor the straws drains out of the side of the screen. Given that, the part of the straw that would be without liquid first would be towards the center and it would spread towards the edges as the straws keep draining. The edges would clear last since all the liquid has to have left the straw for the water to no longer be present at that location. It's the inverse of the TV process itself. It starts at the edges since that's where the ingress of water occurs first.

 

[Powerbook27364]

Since you want to swap out the screen anyway, I would suggest trying to up the temperature slightly to see if that will provoke any improvement, 110 C?

If my vapor pressure of water theory is correct, and assuming the boiling water is following the gas law, PV=nRT, and for our situation, essentially PV=T. Also the volume of the water must remain constant due to volumetric constraint, then P=T. As the temperature increases, so does the pressure. If the pressure is higher, it's possible it could drive more water out of the screen. At a certain point it would no longer be possible to up the temperature since the components will be damaged, but until we reach that point, in cases of extreme TV, it may be worth attempting to increase the temperature incrementally.

For anyone wondering why the center cleared up and not the rest of it, It does support my vapor pressure theory involving water. Think of the water in the screen as a series of straws that are holding liquid, running from the edge to the center of the screen. As it is driven out of the monitor the straws drains out of the side of the screen. Given that, the part of the straw that would be without liquid first would be towards the center and it would spread towards the edges as the straws keep draining. The edges would clear last since all the liquid has to have left the straw for the water to no longer be present at that location. It's the inverse of the TV process itself. It starts at the edges since that's where the ingress of water occurs first.

Yeah maybe. I can’t do much else so I guess it can’t hurt. I’ll do it tomorrow and I’ll update you guys then. I think I’ll try for 4 hours unless you think it would be beneficial to do more?

 

[Paralel]

Yeah maybe. I can’t do much else so I guess it can’t hurt. I’ll do it tomorrow and I’ll update you guys then. I think I’ll try for 4 hours unless you think it would be beneficial to do more?

I'd probably give it the same amount of time where you saw the most improvement when you did it at 100 and repeat that time. Changing any other variable makes it hard to know if it doesn't work what the problem was, not enough time? not a high enough temperature? etc...

If you actually see further improvement at a higher temp(s) then that would essentially confirm the moisture theory. Any of the other explanations would likely be made worse with increasing temperature.

 

[Powerbook27364]

I'd probably give it the same amount of time where you saw the most improvement when you did it at 100 and repeat that time. Changing any other variable makes it hard to know if it doesn't work what the problem was, not enough time? not a high enough temperature? etc...

Sounds good. I gave it 4 hours initially. I will make sure to take pictures as a comparison before and after.
I doubt time was a problem since I baked it for about 12 hours in all. So maybe my oven just has a variance in actual temperature versus what the oven thinks it is

 

[Paralel]

I look forward to hearing back from you regarding what I hope will be a success, or if not, at least the first step on the path to success.

 

[Powerbook27364]

I look forward to hearing back from you regarding what I hope will be a success, or if not, at least the first step on the path to success.

Well that’s doesn’t seem like a great sign.

Little black dots. Not sure why. Didn’t see them previously. It is cooling down now so it won’t take too long before I can test it

Hopefully those go away after it is cool.

 

[3lectr1cPPC]

Not good, looks like pixel rot. I saw a much worse example on a thread but I can’t find it. Guy had baked his 170 LCD and it fixed the tunnel vision, then a BUNCH of those showed up out of the blue a little while later. Perhaps baking it too long can cause this? I’m still searching for the thread.

 

[Powerbook27364]

Not good, looks like pixel rot. I saw a much worse example on a thread but I can’t find it. Guy had baked his 170 LCD and it fixed the tunnel vision, then a BUNCH of those showed up out of the blue a little while later. Perhaps baking it too long can cause this? I’m still searching for the thread.

That really sucks. It’s gonna be very hard to find a replacement panel. I may be forced to buy a second parts machine and harvest the panel.

 

[3lectr1cPPC]

Yeah. Baking it more was either going to fix it or make it worse, seems we’re now getting evidence that baking it more can cause this. You’ll have to see for sure once it cools down, but that’s what that looks like to me. It was a junk panel either way, I’d be interested to see how bad it tunnels now though. It’s all down to experimentation to get this right, every person testing helps, especially when there isn’t much to lose.

 

[Powerbook27364]

Yeah. Baking it more was either going to fix it or make it worse, seems we’re now getting evidence that baking it more can cause this. You’ll have to see for sure once it cools down, but that’s what that looks like to me. It was a junk panel either way, I’d be interested to see how bad it tunnels now though. It’s all down to experimentation to get this right, every person testing helps, especially when there isn’t much to lose.

It’s been on for about 10 minutes and so far the tunneling is much much better. About an inch in on the right and about half that on the other sides

Side note, do you know if pixel rot worsens with time or stays constant?

 

[3lectr1cPPC]

Are the black spots indeed pixel rot? The other guy’s started much worse, large hole shaped areas that appeared as if they were “bleeding” down the screen. He baked it for longer after that as an experiment and the interesting thing is the many smaller ones around the panel turned into one huge one in the center, but that was all. Areas previously affected were fine then. Still looking for the thread.

 

[Powerbook27364]

Are the black spots indeed pixel rot? The other guy’s started much worse, large hole shaped areas that appeared as if they were “bleeding” down the screen. He baked it for longer after that as an experiment and the interesting thing is the many smaller ones around the panel turned into one huge one in the center, but that was all. Areas previously affected were fine then. Still looking for the thread.

They are still there unfortunately. Not changing so far. There isn’t very many but it’s enough to distract you if you are trying to do anything.

With time, the tunnel vision is creeping closer to the center but still not as bad

 

[3lectr1cPPC]

And I’ve made a bloody fool of myself. The thread I was searching for was this one
Check the first page, you’ll see what happened to the other guy’s display. And I also remembered wrong, his turned into 2 large holes, not one. Sucks that your panel ended up this way. I wonder if the long heat exposure damaged the layers in some way. @techknight would probably be able to get a better idea of what’s going on, so could @Paralel probably.

 

[Powerbook27364]

And I’ve made a bloody fool of myself. The thread I was searching for was this one
Check the first page, you’ll see what happened to the other guy’s display. And I also remembered wrong, his turned into 2 large holes, not one. Sucks that your panel ended up this way. I wonder if the long heat exposure damaged the layers in some way.

It sucks but I did know it had a chance of doing this when I bought it. Maybe I will replace the screen or buy a passive matrix model so I have a working PowerBook.

 

[3lectr1cPPC]

I’d try for another 170, I’ve got both a 170 and a passive matrix 145 and the difference in quality is night and day. Any passive panel will also need to be recapped. If you find one with less tunnel vision, baking it will probably yield better results. Your first panel had a pretty bad case compared to many. Also worth noting, that first guy’s panel actually developed the dead pixels before being baked, I misremembered. Know I don’t know what to think on what caused that damage.

 

[Powerbook27364]

I’d try for another 170, I’ve got both a 170 and a passive matrix 145 and the difference in quality is night and day. Any passive panel will also need to be recapped. If you find one with less tunnel vision, baking it will probably yield better results. Your first panel had a pretty bad case compared to many.

I see the quality trade off and recapping isn’t too much of an issue. Maybe I will try for another 170 if I can get one cheap for parts. Hopefully it doesn’t have TV or if it does, hopefully it is fixable.

 

[Powerbook27364]

unfortunately there doesn't seem to be any cheap 170s, several parts laptops are going for over $100 each, for a dead machine I find that pretty high.

 

[3lectr1cPPC]

If you bide your time, you can probably snag one for closer to $50-70. Checking sold I see a couple, although one was a hilarious hybrid machine that was labeled on the computer as a 170 but clearly had a passive matrix display, contrast slider and all, hah.

 

[Powerbook27364]

This may serve as a warning to people with such a bad tunneling effect that fully darkens the screen. Be careful with how much you bake I guess