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Tunnel Vision On Monochrome Active Matrix Powerbooks
Posted by: barrakuda on 2020-01-19 16:59:28 How about putting the screen in a large enough food dehydrator instead of an oven?
Posted by: geedubya on 2020-03-10 09:46:45 Barracuda: using a food dehydrator sounds promising. Right temperature range, airflow for moisture extraction, timer — plus it avoids stink & contaminaton in your kitchen range. Have you got one to try it?
Posted by: GregorHouse on 2020-04-23 10:34:14 Winner winner screen dinner! It’s a PB 170 screen with a huge tunnel problem here. Corners begin to dark after a few seconds and in a two minutes nearly all of the screen is dark. According to major opinions in this thread, I will bake for three or four hours at 80-90ºC and see what happens. Also I put one silica bag in every corner after taking the picture. I’ll post the results.
Posted by: PB145B on 2020-04-23 16:22:14 Winner winner screen dinner! It’s a PB 170 screen with a huge tunnel problem here. Corners begin to dark after a few seconds and in a two minutes nearly all of the screen is dark. According to major opinions in this thread, I will bake for three or four hours at 80-90ºC and see what happens. Also I put one silica bag in every corner after taking the picture. I’ll post the results. View attachment 33050 I am very curious to see the results of this! Hope it works!
Posted by: Juror22 on 2020-04-23 20:57:42 How about putting the screen in a large enough food dehydrator instead of an oven? I like this idea, if it turns out that it is moisture. next we should try the bucket of rice for a week or silica gel
Posted by: GregorHouse on 2020-04-24 07:41:23 It worked pretty well actually. First pic is 10 minutes after powering on. Second pic is 20. Darkening is still there, but it improved a lot. My bad I didn’t take pictures before, but by the time the mac boots to desktop, almost all the screen was black. Also, after shutting down the menu bar was still visible for a couple minutes, like if it had burned the screen. I’m baking it again, but I think this is the better I can get. At least it’s usable now.
Posted by: GregorHouse on 2020-04-24 23:39:36 Second cooking was a huge success. I left the display in the oven for the whole afternoon and the tunnel effect has completely gone, while the screen still “burns” and windows and menu bars are still visible for a few seconds. Nothing to do with a passive display such as PB 100 or 140, but way more noticeable than the Portable, for example. I have to keep in mind that this laptop was my uncle’s, who used it 30 years ago to translate books, so the screen has large mileage. By the way, as the case has enough room I left the silica bags inside, hoping this will prevent moisture from getting inside the display and delaying the problem to show again. Thanks everybody for your help!
Posted by: cheesestraws on 2020-04-25 02:20:41 That's great news and really nice to see 🙂
Posted by: bibilit on 2020-04-25 04:49:13 Hi, nice to see. Did the screen was heated up and down ? by the way, where are you based, this SSW is unusual (Catalan I guess ?) never seen before, never thought either it was available
Posted by: bengi3 on 2020-04-25 09:46:43 Any idea on how to seal the thing as a preservation measure?
Posted by: GregorHouse on 2020-04-25 22:34:33 Bingo! Yes, that’s catalan. I’m from Barcelona. Not a lot of OS’s were translated to Catalan. Only 7.1 and 7.5.3 I think, or at least I have. And then nothing until Lion. About the screen, I think it turned black while it was in the oven, it was hard to see. I kept it between 80 to 90ºC for about six hours twice. Temperature above the boiling point, to avoid expanding gases and I let it cool down for the whole night inside the oven. I didn’t open the door during the process to avoid abrupt thermal changes that could crack the screen. I don’t know how to reseal it. In fact, I didn’t disassemble the screen itsel. I read in another post someone who tried and didn’t go very well, so I masked the back of the screen with aluminium foil and the whole screen inside the oven. The best I could think of to prevent this from happening again was to keep the silica bags inside.
Posted by: bibilit on 2020-04-26 00:37:48 Ok, hope you and your relatives are fine from this sad situation, I have family in Spain and holding my breath for each and every one. I spent a couple of stays in Barcelona and enjoyed every minute. I have a 170 suffering from the tunnel vision as well, think I will try to cook it like you. I disassembled the screen and heated the inside with hot air, had troubles when resealing it, had to do it several times ( the image was distorted) in the end, still have the TV, the hot air didn’t cure it.
Posted by: GregorHouse on 2020-04-26 03:27:15 We’re fine, thanks! It seems the worst is over. My wife works in a hospital and she says the situation is getting better. Refering to the screen, I think the key is heating it for a long time and in a dry environment to let the moisture go out.
Posted by: bibilit on 2020-04-26 06:53:52 Gracias, un saludo de Francia.
Posted by: Trash80toHP_Mini on 2020-04-26 10:36:47 Glad to hear everyone's OK. Is "Tunneling" different from "Vinegar Syndrome" and if so How? We had a great thread going about the latter.
Posted by: bibilit on 2020-04-26 11:17:05 Yes both are different. Tunneling is when the screen seems ok, but after a while corners are darker and darker. the middle of the screen remains ok for a while then all the screen goes very dark. The vinegar syndrome is an issue in the polarizer. The issue is visible, screen seems damaged on the outside and a strong smell is present (hence the name)
Posted by: GregorHouse on 2020-04-26 11:40:45 True, as I know vinegar syndrome is a common issue relative to all LCD panels, where the polarizing film glue deteriorates, making bubles, watermarks or even cracking the film. This deformations on the film causes image distortions, stains and so. The tunnel effect is a particular issue of the PB 170 screen (and many others, I guess) causes by a design or manufacture defect, that let moisture get inside the screen “sandwitch”. It gets worse if you keep the computer in a cold and wet room, like a garage or basement. In my case, the computer was stored in a electric closet, where the electric meter, for almost twenty years.
Posted by: Papichulo on 2020-04-26 12:29:28 How do you keep it from tunneling? My 170 has a problem were it has 3 lines going down on the far left of the lcd when on but it goes away when i put pressure on the side of the screen. Its not the lcd cable. Thats good everybodys safe.
Posted by: Juror22 on 2020-04-26 13:16:13 I kept it between 80 to 90ºC for about six hours twice. Temperature above the boiling point, to avoid expanding gases and I let it cool down for the whole night inside the oven. I didn’t open the door during the process to avoid abrupt thermal changes that could crack the screen. Thanks for posting your 'recipe' and the in-process pictures. I would like to try to replicate your results with a PB180 screen that is showing signs of the tunneling issue. It will take a bit to sort out which oven to use and the correct settings, so it may be a while before I report back, but its good to see progress here. Also glad that you and yours are safe.
Posted by: GregorHouse on 2020-04-26 13:31:31 Thanks for posting your 'recipe' and the in-process pictures. I would like to try to replicate your results with a PB180 screen that is showing signs of the tunneling issue. It will take a bit to sort out which oven to use and the correct settings, so it may be a while before I report back, but its good to see progress here. Also glad that you and yours are safe. I used a regular size oven, upper and lower heating. I think it’s better to use one of these rather than a smaller one, in order to keep a safer distance between the screen and the heating element. Don’t trust the oven’s thermostat, by the way. Buy a cooking thermometer, they’re cheap and more reliable. How do you keep it from tunneling? My 170 has a problem were it has 3 lines going down on the far left of the lcd when on but it goes away when i put pressure on the side of the screen. Its not the lcd cable. Thats good everybodys safe. I kept four silica bags in the display assembly, I hope this will do the trick, at least for some time. About your problem with the lines, I’m not an expert, but it sounds to me like some kind of faulty contact inside the lcd panel itself. The display sandwitch is secured by a metal frame that has a lot of passing-through “legs”, that are twisted in the back of the screen. Make sure that they tight, otherwise I can’t help
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