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

[3lectr1cPPC]

I only ask because I have heard not to bake motherboards (to reflow) in the same oven as food goes in for that reason. Ive done so a couple times a while back without any negative effects but if it’s not a good idea then it’s not a good idea. The LCD bake is a lower temperature though, but it could still possibly burn off residual flux? In any event, I need to source an old toaster oven to use for reflowing.

 

[bwinkel67]

I can see that with motherboards, esp since they can have lead solder. I think the LCD panel is pretty clean having a metal housing and glass plating.

 

[Powerbook27364]

I just attempted the baking of the lcd to get rid of tunnel vision and I had almost no change. My tunnel vision is very severe and completely darkens the screen over the course of about 20-30 minutes. After baking there is now a small section of the center that is not dark. How should I proceed from here?

 

[3lectr1cPPC]

What temperature did you use and for how long? General consensus seems to be that 100 degrees Celsius for around 5 hours makes a good difference.

 

[Powerbook27364]

I used 100C for 4 hours like a previous post mentioned.

Thanks for such a fast response even thought this is quite an old thread.

 

[Powerbook27364]

I used 100C for 4 hours like a previous post mentioned.

Thanks for such a fast response even thought this is quite an old thread.

I’m wondering if I should just bake it again maybe for a little longer next time.

 

[3lectr1cPPC]

Sure, try 5 more hours. Some I believe have even gone up to 8 if I remember correctly. Too long doesn’t seem to cause damage, too much temperature does. Sounds like yours had a very severe case so it would make sense if it took longer. Good luck!

 

[Powerbook27364]

Sure, try 5 more hours. Some I believe have even gone up to 8 if I remember correctly. Too long doesn’t seem to cause damage, too much temperature does. Sounds like yours had a very severe case so it would make sense if it took longer. Good luck!

I will try tomorrow. I’ll update you after it is finished. Hopefully I see some improvement and if so I will just work from there. Thanks for the well wishes.

 

[3lectr1cPPC]

Yeah, no problem. Let us all know how it goes!

 

[Powerbook27364]

Yeah, no problem. Let us all know how it goes!

Finished it and put it together it’s much better and takes longer to start. Still pretty bad though. It was completely dark before.

Edit: there is ghost pixels or something. That window is not open but previously was.

 

[joshc]

How hard is it to get the video signals out of a PowerBook logicboard? Just wondering how doable it is to hook up a modern screen, and then the challenge would be finding something that fits the dimensions of the PowerBook display bezels... just a thought.

 

[3lectr1cPPC]

Yours seems to have been really really bad then to begin with, usually the whole screen won’t vanish like yours did. Ghosting/burn in seems to be another tunnel vision related issue. Same cause, and it goes away when the display is fixed. I suppose it wouldn’t hurt to bake it longer if it keeps helping? Worst that happens is the panel does but it’s already pretty much junk as is right now so it can’t hurt.

Here’s a time lapse I shot of my 540, over an hour.

Any idea on what’s causing the yellow corners? Seems to be backlight related but NOT a worn out tube as the rest of the screen is fine.

 

[Powerbook27364]

Yours seems to have been really really bad then to begin with, usually the whole screen won’t vanish like yours did. Ghosting/burn in seems to be another tunnel vision related issue. Same cause, and it goes away when the display is fixed. I suppose it wouldn’t hurt to bake it longer if it keeps helping? Worst that happens is the panel does but it’s already pretty much junk as is right now so it can’t hurt.

Here’s a time lapse I shot of my 540, over an hour.

Any idea on what’s causing the yellow corners? Seems to be backlight related but NOT a worn out tube as the rest of the screen is fine.

Yeah I think I will bake it all day tomorrow just to try because it’s pretty hard to use currently. Stops getting worse after 30 mins only. If worst comes to worst I may have order another screen. Hopefully it will be fixed after the next bake. Fingers crossed!

The corners look like liquid damage, but I may be wrong. Not entirely sure.

 

[Powerbook27364]

Alright I just finished baking the display for another 6 hours.

Unfortunately I have not seen any difference in the tunnel vision. I’m about to give up. I have baked it for 12 hours total and its still very bad and hard to use.

I guess I just should deal with it or replace it.

Thanks for the help but I think it may be too severe to fix at this point.

 

[jeremywork]

How hard is it to get the video signals out of a PowerBook logicboard?

I thought this too, but for the purpose of bodging an extension together to attempt running alternating test patterns while at temperature, to see if this adds anything to the result.

 

[3lectr1cPPC]

You mean run the LCD while it's being baked? Sounds like that would very quickly cause components on the driver board to overheat and fail.

Sorry to hear that your display wasn't recovered by this. Too far gone I suppose.

 

[Powerbook27364]

You mean run the LCD while it's being baked? Sounds like that would very quickly cause components on the driver board to overheat and fail.

Sorry to hear that your display wasn't recovered by this. Too far gone I suppose.

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.

 

[jeremywork]

You mean run the LCD while it's being baked? Sounds like that would very quickly cause components on the driver board to overheat and fail.

Yeah, basically it can't hurt to try if the panel would be considered junk anyways. To mitigate heat in unwanted areas, you'd probably only need something like a marine lamp on a dimmer and a metallic shroud to direct the light into the face of the LCD. The backlight could be separated, and a fan could be run over the driving electronics to keep their temperature down. A simple thermometer could help monitor the temperature of the surface of the panel to prevent melting anything, and you may even be able to literally monitor the progress if mounted against a piece of diffuse glass, for instance. I'd be willing to try, but I haven't even yet seen this symptom in person.

I may revisit it at another time

If you ever swap in a new panel and don't want to experiment yourself, send me a pm and I'll pay something fair for the damaged one.

 

[imactheknife]

I think its power related?? not moisture..if i turn on my powerbook 180 on, boot up, shut down and turn on you can almost see the tunnel vision oval starting at more centre of screen and working out..or maybe not the same thing?? Thoughts?

 

[Powerbook27364]

Hmm that’s interesting. My 170 doesn’t seem to have that. Maybe some other people might.

May be interesting to investigate. Hopefully we will eventually find a better cure.