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

[Powerbook27364]

Oh that may be hard to find for me. I bought mine after the previous owner recapped its boards. I should be able to get all of the rest at least.

 

[3lectr1cPPC]

Don’t think the CC is too picky but some are. Logic board photo would be awesome though.

 

[Powerbook27364]

Don’t think the CC is too picky but some are. Logic board photo would be awesome though.

Here’s a logic board photo. I’m working on getting the values for the analog board now.

 

[Powerbook27364]

I’m not sure if I’m able to get all the values of the Alan of board. I have no way to discharge the crt safely so that may be out of my doing.

 

[3lectr1cPPC]

Don’t worry about it. I can find the values online elsewhere. Thanks for the LB photo.

 

[Powerbook27364]

Don’t worry about it. I can find the values online elsewhere. Thanks for the LB photo.

I’m working on it but it may take me a little while so I’ll follow up in a bit.

 

[3lectr1cPPC]

Alright, but the values are already online here: https://recapamac.com.au/macintosh-cc-analog/
I could use an image, but I’ve got the values. Don’t risk a shock though if you don’t have the equipment to discharge a CRT. You’ve already helped a bunch!

 

[Powerbook27364]

Turn out the plastic mounts for the crt are cracking so it has to be done anyways to repair them. I’ll be sure to get a photo or two while I’m at it.

Crt has been discharged so all I have to do is remove it.

 

[Powerbook27364]

 

[3lectr1cPPC]

Thanks! Good luck fixing your CRT mounts.

 

[Powerbook27364]

Repair went well! Back together and working great once again (or as great as a color classic can work)

 

[3lectr1cPPC]

Good to hear!

 

[ehdjej38389]

If you have a replacement lcd for the powerbook duo is it possible to seal it yourself to prevent moisture from getting into it

 

[bwinkel67]

If you have a replacement lcd for the powerbook duo is it possible to seal it yourself to prevent moisture from getting into it

Trying my best to squash the "old wives tale" of it being moisture. Unfortunately this thread has become more than just about Tunnel Vision as people are posting about other fixes, but early on we had a robust discussion. I've since reached out to someone that's played with creating their own LCDs and they doubt it's moisture since the liquid crystal is so miscible that if moisture got in, it would just mix with it and never leave. The idea of sealing is more about preventing panel separation so the crystal molecules stay separated at the correct distance and can align to block light from coming through.

 

[3lectr1cPPC]

I agree that this thread has sort of turned into a general TV thread (and PowerBook duo thread even for a bit…). Don’t mind myself, but if we’re going back to productive discussion about the root cause of it then so be it

I think all the discussion here has been productive though. The old thread from 2013 never went over these dead pixels that have popped up for a few people. The info keeps expanding as more people test.

 

[Unbounded_Villain]

People used to think plastic was forever, but it’s not. Early 1960’s Barbie dolls have vinyl faces that look shiny because the plastic is destabilising and returning to oil. Other early plastics are becoming brittle, again, from destabilising.

It’s more likely that the type of plastic used for active matrix displays is no longer stable. When people bake the displays they’re not removing moisture, they’re stabilising the plastic again theough heat and helping it re-bond.

 

[3lectr1cPPC]

I doubt that the plastic would begin to fail in this way as early as 2002 when I can see the first reports of this problem. Would have only been 10 years old at the time.

 

[Unbounded_Villain]

If they were exposed to UV light they would indeed fail that fast. Those dolls I talked about started destabilising in the 80’s. And for that matter, PoweMac plastic cased became brittle from UV exposure after around 10 years as well.

 

[Powerbook27364]

Just got a duo 280 the other day and it has tunnel vision so that will be posted here soon.

Probably going to end up baking it but not sure as of yet.

 

[Powerbook27364]

Just noticed something strange with my PB 170. Tunnel vision has seemingly lessened over time since the baking but it now has very strange behavior on its display.