• Hello, Guest! Welcome back, and be sure to check out this post for more info about the recent service interruption and migration.

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

techknight

Well-known member
ive noticed that with tunnel vision displays is a form of "stiction" where there is memory of the crystals stuck in place. Happens on a portable i have.

I wonder if its just the liquid crystal itself going bad or breaking down. Honestly idk at this point
 

3lectr1cPPC

Well-known member
Maybe we'll get to the bottom of it someday. I'll have to bake the 540's screen when I get a hinge fix part printed for it.
 

Cedsrepairs

Well-known member
It is very frustrating for us laptop owners.
Of course I realize some things just don't live forever, but if so these 1x0 laptops will be impossible to power on with the built in display in the next 5 years.
 

LaPorta

Well-known member
Is this limited to certain models, or all? I’ve got a Portable, 1400, iBook G3, and Duo 2300…and I’ve never seen this. Did I just get lucky?
 

3lectr1cPPC

Well-known member
Tunnel Vision only affects active matrix monochrome/grayscale displays. Anything passive matrix and active matrix color doesn’t have the issue. We don’t even know if every active monochrome is affected because the Apple laptops with them only used hoseiden branded ones. If any PC laptops shipped with one not made by hoseiden, it would be interesting to see if they also have the fault.

Anyway, that means that the 100, 140, 145, 150, 160, 165, 190, etc are not affected because they’re all passive matrix. The only apple laptops affected are the 170, 180, 540, Duo 250, Duo 280 and the portable. Although, the portable doesn’t get it as often as the PowerBooks do for whatever reason. It does happen though. It’s been confirmed that the Portable, 170, 180 and the 540 have hoseiden screens, not sure about the Duos. I also know that Hoseiden made the screens in some 5300cs and possibly others, but they don’t have the issue because they aren’t active grayscale or monochrome.

People often confuse vinegar syndrome (polarizer failure) with tunnel vision. They aren’t the same thing and vinegar syndrome can be fixed by replacing the polarizer layer. Tunnel vision is an issue with the LCD itself.
 

Cedsrepairs

Well-known member
Hey thanks to your post I just realized one of the things I fixed in the past is called "vinegar syndrome" !
Didn't know this had a name. The polariser seemed to be glued to the glass, I had to remove it entirely and replace it with something else.
 

3lectr1cPPC

Well-known member
Yep, that’s what you’re describing. It seems to be more common on passive matrix displays for
Some reason, although I’ve seen plenty of active matrix color ones with it as well. Strangely enough I’ve never seen it on an active matrix mono/grayscale lcd though.
 

3lectr1cPPC

Well-known member
I also know that Hoseiden made the screens in some 5300cs and possibly others, but they don’t have the issue because they aren’t active grayscale or monochrome.
Correction, this is wrong. I got Hosiden (I was spelling it wrong the entire time) confused with Torisan.
 

bibilit

Well-known member
I used to have two 170 at some point, one had an orange hue screen, while the other have the more commonly found green/grey one.

The first never had the issue, while the other is badly suffering from TV... probably two brands i agree.
 

3lectr1cPPC

Well-known member
rats... I've never seen any evidence that the 170 shipped with multiple LCD manufacturers, although I've heard plenty of accounts of varying backlight colors (but never orange!). perhaps that one just had a high hour CCFL tube that had gone really yellow? Mine (which isn't affected at all) appears to have the common Hosiden screen, although I've never had the display assembly apart. I can't easily check either because one of the hinge standoffs is broken and causes the screw to spin... I'll have a look whenever I get a hinge fix part installed in it.
 

bwinkel67

Member
I wanted to give an update on my 100 degree celcius baked PB180 after 6 months. Now I don't use it daily but when I do use it, it's running for hours. I even taught a class with it recently to demonstrate cooperative multitasking to students in an operating systems class (the old Mac's are a great example for it). In any case, the screen has been perfect so far, no tunneling. When recording a video you can see it flicker the refresh on the left side (when there is a black image -- I was running SoftPC with its white text on black screen) but there is no sign of darkening. I haven't tested camera angles to see if it would also flicker on the right...though the bulb is on the left, so that could be the source of the flickering.

The machine with a fixed LCD is just a perfect Mac platform to have. I even got the video cable and VGA adapter to get color output (that's how I taught my class on a projector). Nice to see a color picture out of my PB180 (and amazing that a '92 machine's control panel interface for monitors is pretty much what we have today). Once I track down an adb keyboard, I will be able to close the lid and use it like my old Mac IIsi I had back in the day...but smaller and portable :) So, the baking can fix things in some instances. Is it moisture or dried up edge adhesive? No way to know although the laptop is not stored in a bag with rice, etc, so there is no moisture control on it. I don't expose my stuff to high moisture on purpose and we have central AC so the place doesn't get overly humid. I suppose the only way to know is to see how it holds up over the long haul, so no exciting updates to give weekly.

I saw the September 10th post with the speckled screen. I would say 100 degrees celcius was the magic number for me for 4 hours (plus left it in as the oven cooled down). Weeks earlier I had tried 85 degrees celcius for 9+ hours and that had no impact (that's why I'm reluctant to think it's moisture related) . I suppose it could have been a cumulative effect, though again, there was absolutely no improvement at that lower temperature for my unit (I know that's not true for all). Reminder that we have a gas stove which maintains good temperature plus I added two pizza stones to help keep it from fluctuating.
 

bwinkel67

Member
Which reminds me of the one tests I wanted to try but again, fixed the screen before I thought of it: place PowerBook in refrigerator but turned on. Before anyone does that though, does 40 degrees damage a laptop? I've seen people use a laptop outside in the winter time while it's in the 30's and they are waiting for half an hour for a bus...maybe that's not the same? In any case, putting it in a refrigerator will see how temperature impacts tunneling. Although this time of year, one could also just use it outside when it hits in the 40's to see how tunneling is impacted by the temperature (i.e. does it take longer to get there). Not sure what information that gives other than having one extra data point (how does temperature relate to humidity and/or separation of adhesive layers, etc...). Just an idea.
 

3lectr1cPPC

Well-known member
I could try that on my 540. Is it really a good idea (for the oven) to use the same oven food goes in? Harmful chemicals?
 

bwinkel67

Member
Don't know...but my wife and I are still kicking around and the extra arm that's growing out of my back has been useful :) I don't think it's heated enough to release lots of chemicals into an oven.
 
Top