Powerbook Tunnel vision fix

[bibilit]

I have collected a nice Powerbook 170, but unfortunately suffering from the infamous tunnel vision issue.

Has someone found a fix to the problem ?

Heating the panel or using rice to solve this issue was posted at some point.

 

[techknight]

Baking will fix it, HOWEVER there is a very fine delicate balance to temperature. The temperature you need to really drive out the moisture, the ribbons and especially polerizing film wont survive it. 

But if the temperature is low enough for the polerizing film to survive, it would take a very long time to bake. 

My thought is potentially 100 degree heat thats tightly regulated with desiccant over several hours to drive out the moisture but prevent damage to the polerizing film. 

 

[Byrd]

I can't help thinking that baking an LCD display would result in tears.  Too many variables, fragile components, risk of warping and melting.

Some members have reported hacking in a LED strip light to replace the existing backlighting is possible, but I've never seen a test case or evidence of this being a success.

 

[techknight]

I can't help thinking that baking an LCD display would result in tears. 

Again that depends on the process used. Sure if you run it up to 300+ degrees yea. lol. 

 

[trag]

It would be great to have a programmable Thermotron (thermal test chamber) to experiment with...    You could create all kind of profiles.    Might even work, in one of those, to take the temperature low and see if the dehumidifying qualities of the cooling loop will get the moisture out.

 

[techknight]

Huh. Never heard of that instrument. That would be neat. 

 

[Cory5412]

I live in Arizona and when I first got my 180, it had the tunnel vision issue, but it has since gone away. I believe it has been confirmed the issue is the humidity. Popping the mahine (or even just the display) would probably get moisture out of it, but there are other ways to do that which I would suggest might work better or be less potentially problematic.

Once you have de-humidified the machine, however you prefer, (air conditioner? box and desiccant?, rice in a box?) there are a few other threads about how to re-seal the LCD display to prevent further tunneling.

 

[trag]

Huh. Never heard of that instrument. That would be neat. 

It's a brand of thermal test chamber.  It has a cooling loop (usually 2, to hit low temps) and a heater system.  Also a controller and an insulated test chamber, with a conduit through which one can run necessary connections to the device under test.  We had one at my previous job.   I got very acquainted with it.   And every time one particular manager (really nice guy, just dropped his phone a lot) dropped his phone in the toilet he'd come by and ask me how to program it....

 

[bibilit]

The powerbook was in a wet basement at some point i think, feet were mouldy.

Removed the glass from the LCD assembly and tried heating with an hair dryer for a couple of minutes, borders were black in some areas (again confirming the humidity issue), refitting was a bit of trial and error, until picture was fine again (distorted first two times)... i realized some patterns were present to lined up both units together.

No improvement so far, tunnel vision is pretty quick to spread, a couple of minutes at best.

Will keep it in a dry place for a while to see how things goes.

Had another unit not so long ago, with no issue, but LCD was different (not so bright, almost amber in colour... any clue ?)