Interesting, and good to know. So far yours is the only reference to tunnel vision on those that I've found.
Macintosh Portable horror story
- Thread starter wottle
- Start date
Was it part number LD1028-020020? This all makes me wonder more what LCD the PS/2 CL57 SX used.
www.thinkwiki.org
TFT display - ThinkWiki
Probably, I forget. im at work and the machine isnt in front of me but it suffered from tunnel pretty badly. I bought another panel on ebay and it had the same problem plus ribbon delamination. I used that one as my baking experiment. Failed.
I'll have to ask solidpro on VCF whether he's run into this. That guy has the largest collection of ThinkPads that I know of and has repaired numerous models that should have that Hosiden LCD according to that list.
Very interesting that BOTH you had ran into that issue.
I definitely think it's somewhat related to storage conditions. My 170 that is unaffected by tunnel vision was stored very well over the years based on all I've examined - I highly suspect it was sitting in its bag in a closet, not in a damp basement like most of the stuff I end up with smells like.
Very interesting that BOTH you had ran into that issue.
I definitely think it's somewhat related to storage conditions. My 170 that is unaffected by tunnel vision was stored very well over the years based on all I've examined - I highly suspect it was sitting in its bag in a closet, not in a damp basement like most of the stuff I end up with smells like.
Funny you mention, I have a 180 thats starting to tunnel. It didnt when I got it over 10 years ago, and its been stored in my climate controlled house ever since. So yeah it might be a factor in potentially decelerating the effects, but it will still happen regardless.
I do think its a bad chemical mixture of liquid crystal that breaks down with time accelerated by heat. Just like vinegar syndrome.
I've only run into one Hosiden panel (that I know of), and it was the one in my CTX EzBook 800. I only had it on for maybe an hour total as the laptop got varta bombed and died after cleaning, but it worked while I had it on. It was a much newer panel - circa 1998. It was yellowing at the top though, but that's fairly normal on LCDs from any vendor.
It was TFT Color 800x600.
Beyond that I have the 170 which is still fine, and a PowerBook 540 that is affected. It's got a far more interesting failure though, some sort of what looks almost like moisture damage, although there are no other signs of it. The corners on the bottom are yellowed in a very uneven way. I took the panel apart and it's the backlight diffuser. I thought it was just a freak failure, but then I've seen a couple more on eBay that had the same issue. Very odd.
I'll try to find an image.
It was TFT Color 800x600.
Beyond that I have the 170 which is still fine, and a PowerBook 540 that is affected. It's got a far more interesting failure though, some sort of what looks almost like moisture damage, although there are no other signs of it. The corners on the bottom are yellowed in a very uneven way. I took the panel apart and it's the backlight diffuser. I thought it was just a freak failure, but then I've seen a couple more on eBay that had the same issue. Very odd.
I'll try to find an image.
Yeah it will probably happen to all of them eventually. I'm counting the days till I see it start on my 170.
Yeah the yellowing is normal as the UV and heat from the CCFL affect the diffuser light spreader thing. A lot of my laptops are like that now.
This photo was taken after leaving it on for a few hours to show the tunnel vision but you can also clearly see the weird yellowing in the bottom corners. It's the diffuser layer itself and is not something that can be cleaned off.
Yes. The 540 panels don't have a specific part number printed on them for whatever reason, but it's a Hosiden panel. I believe the best or one of the best they made, it can run in 256 grays mode (although I think it's been calculated to only display around 64 shades).
macdat.net
PowerBook LCD Index - MacDat
macdat.net
Yes. The 540 panels don't have a specific part number printed on them for whatever reason, but it's a Hosiden panel.
PowerBook LCD Index - MacDat
Yeeaahhhh thats what i suspected. Its looking more and more like a defective chemical mixture.
Honestly, I've just heard so many hypothesis from so many people that I have no idea what to think. Moisture due to defective seal? Defective seal itself? Bad glue? Bad liquid crystal? I wish there was a way to know for sure.
The one thing I wonder is why baking a panel would improve the condition if it was in fact defective liquid crystal. I know it did not work for your color panel, but it does work on the monochrome ones (and I believe the grayscale panels too), depending on how bad it's gotten.
The one thing I wonder is why baking a panel would improve the condition if it was in fact defective liquid crystal. I know it did not work for your color panel, but it does work on the monochrome ones (and I believe the grayscale panels too), depending on how bad it's gotten.
But it centers around Hoisden. That's the common denominator here. What can be different between them and every other LCD manufacturer? Thats whats going through my mind at the moment. Theres a lot of process variations, sure. but idk what to think anymore besides that.
Definitely a Hosiden issue, we know that for sure, but that's all we know.
On a different slightly related note - check this eBay listing out:
Here's something we didn't know previously. The 540c shipped with Hosiden color panels. They must be very rare - there's BEEN a lot of discussion about LCD vendors in the 540c because people have debated whether the Sharp or the Toshiba panel looks nicer, but no one's brought up Hosiden as a vendor they found in theirs.
On a different slightly related note - check this eBay listing out:
PARTS LOT Vintage Apple Macintosh PowerBook 1400 500 520 540c +3 EXTERNAL Floppy | eBay
1 (one)PowerBook AC Adapter M1893. 1 (one)PowerBook 520 screen. 1 (one)PowerBook 540c screen. 2 (two)PowerBook 500 backs. + 3 (three) HDI-20 External Floppy disk drives. 3 (three)HDI-20 External Floppy disk drives.
www.ebay.com
Here's something we didn't know previously. The 540c shipped with Hosiden color panels. They must be very rare - there's BEEN a lot of discussion about LCD vendors in the 540c because people have debated whether the Sharp or the Toshiba panel looks nicer, but no one's brought up Hosiden as a vendor they found in theirs.
And that would be the actual panel used. Same situation where they only have a serial number sticker, no direct model number. I know that's a color panel though - the grayscale ones say "MTFT" instead.
I have a 540c which has a weird halo in my junk horde as well, I never took it apart to figure out why that was yet or tinkered with it.
Was not a case of vinegar syndrome? That can sometimes cause a halo effect but it would also be visible when off and is usually more colorful.
Could be that you had the Hosiden panel.
This is all very interesting to me because until your 750C, I had NEVER heard of a case of this issue on a color screen, I had thought the Hosiden color panels were not affected. They were rather common in all sorts of laptops, and I had never heard a mention of a single case.
Could be that you had the Hosiden panel.
This is all very interesting to me because until your 750C, I had NEVER heard of a case of this issue on a color screen, I had thought the Hosiden color panels were not affected. They were rather common in all sorts of laptops, and I had never heard a mention of a single case.
Of course i had to be the lucky one!
On the 540c, i dont know yet. it could even be the rear polarizer film, its not the front. I just cast it aside to figure it out another day.
On the 540c, i dont know yet. it could even be the rear polarizer film, its not the front. I just cast it aside to figure it out another day.