• Updated 2023-07-12: Hello, Guest! Welcome back, and be sure to check out this follow-up post about our outage a week or so ago.

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

Powerbook27364

Well-known member
Yep, even the portable did. Although it’s never been explainable how portables don’t usually get TV. They can get it, but usually don’t. This is also far from the first time an image of a 170 LCD has been posted, oldcrap.org has a few. The guy who runs that site has a working example of every 100 series PowerBook, all documented! It’s a great resource.
It seems to be quite rare to see an unaffected PB170 so it’s good to make sure it’s the same brand because it would be a pretty big discovery if they found a non Hosiden screen.

I wonder if maybe they used better materials possibly on the portables and that’s why they are less affected. Possibly better sealant or better adhesive between layers?
 

3lectr1cPPC

Well-known member
it would be a pretty big discovery if they found a non Hosiden screen.
Yep that's why I cracked mine open. I'll have it apart again soon to fix the hinges, then I can finally take it mobile after owning it for a year now! And yes, I was extremely lucky to not have an afflicted unit. They're out there, but not common. I believe it has much to do with storage, so many laptops I get stink of basement, this one didn't.
 

Powerbook27364

Well-known member
Yep that's why I cracked mine open. I'll have it apart again soon to fix the hinges, then I can finally take it mobile after owning it for a year now! And yes, I was extremely lucky to not have an afflicted unit. They're out there, but not common. I believe it has much to do with storage, so many laptops I get stink of basement, this one didn't.
Good luck with the hinge repair. Hope it works well for you.

My 170 seems to have been one of those stored in a basement for the past 20+ years. You win some you lose some. Before tv begins it’s quite awesome to use.
 

3lectr1cPPC

Well-known member
I cracked the 540 open and figured out pretty quick what the yellow corners issue is
D9C8670E-F670-4223-9313-36151552C704.jpeg
Whatever has made this bit of the backlight diffuser turn yellow isn’t something that will just wipe off. Any way I could mask it somehow? Or what even caused it to begin with? No signs of liquid inside the computer.
 

Powerbook27364

Well-known member
I cracked the 540 open and figured out pretty quick what the yellow corners issue is
View attachment 50845
Whatever has made this bit of the backlight diffuser turn yellow isn’t something that will just wipe off. Any way I could mask it somehow? Or what even caused it to begin with? No signs of liquid inside the computer.
I haven’t seen anything like that before...

Looks like liquid but there aren’t any other traces. The best option is to replace it. There may be a way to cover it up with something but I can’t think of a good way to make the entire screen an even color.

I wonder if you can just put any diffuser in there as long as it’s the right size... not sure if that’s a great idea though.
 

Paralel

Well-known member
Darn, I wish I'd known. I chucked a 540c panel just recently that was smashed. The screen was a goner, but I'm sure the diffuser was just fine. Never thought of keeping something like that as a part.

This is probably the first time I have ever seen a diffuser damaged in such a way.
 

3lectr1cPPC

Well-known member
Very strange… ah well. I’m going to need a donor at some point. This one’s also got a big ol’ scratch down the middle so it isn’t the nicest example, even if I baked it. Rest of the 540’s in great shape though.
At least I only broke one of the clutch cover clips (one of the 6 total, 2 on each clip.)
 

Powerbook27364

Well-known member
That sucks. Those 540s seem to be relatively expensive even when dead. I wonder if you could put something like a piece of paper in between to see if it helps remove the yellowing.

If you can measure the thickness of the diffuser, you should be able to replace it with a new sheet of the same thickness. Not very easy to do but definitely cheaper than buying a new screen.

Those would really be a last effort to save it but both could damage it so I wouldn't really recommend either unless you are going to replace it anyways. I'll try to find a place to get a diffuser.
 
Last edited:

3lectr1cPPC

Well-known member
Yeah, I'm probably going to look into some sort of diffuser replacement, although I don't know where to look for such a thing. 540s seem to be more rare than expensive. I checked eBay and found a few sold listings from recently, and all for for around or under $100. $100 is what I paid for mine, but it was tested and working and came with the charger. Of course, the seller made no mention of the LCD issue and also didn't show a photo of it running, but ah well. It's still perfectly usable as-is at least. And a working 540 in good condition with a charger, 2 non leaking (which means rebuildable!) batteries, and a functioning SCSI drive isn't so bad for that price!
 

Powerbook27364

Well-known member
$100 for that is really good for one of those!
My 170 has a non leaking battery as well but I have no idea how to rebuild that unfortunately.

You should be able to order the diffuser film all over the place from sites like alibaba, though I don't have any experience with them and don't know if they are reliable. They come in different thicknesses and you need to measure the current 540 diffuser to get a replacement.

One thing that may be a problem is if CCFL backlights use different diffusers that the LED backlights used now. I have no clue if they do and cant find too much on the topic.
 

3lectr1cPPC

Well-known member
I'll do some measurements and look into it. What do I have to lose?
Only thing is, it isn't really a film. There are films on both sides of it, but the part that's gone yellow in those corners is more like a thin block of some sort. It's frosted and has a pattern on it. Not sure what the name for that part is.
 

Powerbook27364

Well-known member
Oh I noticed that in my 170 but thought it would be different in the 540. That could cause a large problem in trying to change it
Would you be able to send some more pictures from different angles?

I will have to disassemble my 170 again to see if there is a way to remove the film. I didn't consider that that could have been a possibility.
I may be able to today if I have time, but that would probably be sometime this afternoon
 
Last edited:

Paralel

Well-known member
Yeah, it's a typical patterned plastic diffuser, if I'm not mistaken. The best way to measure the thickness of something that thin is a micrometer gauge.
 

Powerbook27364

Well-known member
Yeah, it's a typical patterned plastic diffuser, if I'm not mistaken. The best way to measure the thickness of something that thin is a micrometer gauge.
I was thinking calipers were a good option but that would probably be better. That's good that its typical! At least its repairable then.
 

3lectr1cPPC

Well-known member

imactheknife

Well-known member
I've found some slight evidence that suggests that Hosiden made LCDs for the PowerBook 5300c (Color active matrix!)
First: https://www.ifixit.com/Guide/Apple+Powerbook+5300+Display+Replacement/5333
This guide uses a mix of photos, but see the ones that appear to be taken from a service guide of some sort? Does that display design look familiar?
Second: This part listing: https://www.thebookyard.com/product.php?cPath=31_669&products_id=23640
Hmm
The one picture is a 3400c lol.. guess they the same case as a 5300?
 

3lectr1cPPC

Well-known member
nope... Just used a 3400c photo in there for some reason. 3400 case is deeper.
rYkoWHUVNI62A1r4.jpg
Here's the photo. Back plate design looks like the 540 grayscale screen. Doesn't match the toshiba or sharp displays these shipped with.
 

Paralel

Well-known member
I've never heard of the color active matrix LCDs having TV. Maybe Hosiden finally figured out how to make a decent LCD screen.
 
Top