M_a_r_c wrote:

> 46e5b254$1@news.povray.org...
>> I heard that you can stick a cell-phone, or an Ipod
>> that has gotten wet into a bag of dry uncooked rice
>> overnight to get the last of the water out.  The rice
>> absorbs the water I guess. You might try some
>> variation on that.
> One of these variations can be Silica gel dryer (the stuff you find in 
> little bags in electronic devices package)

Good ideas both - we've got silica in the desiccators in the lab, I'll 
borrow some of that and give it a go. Apparently it can take weeks to 
properly dry laptops after spillages...

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John VanSickle wrote:
> Bill Pragnell wrote:
> 
>> I will reassemble it this evening and fire it up to see what's what. 
>> In the meantime, does anyone have any additional advice?
> 
> If you persist in drinking around your laptop, get an external keyboard 
> so that you can keep the CPU farther away from the beer.

Yes, or one of those silicone overlays. Isn't 20-20 hindsight a 
wonderful thing! :)

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Well, I put it back together and booted it up last night. I think it 
needs some more drying time :(

I think the HD and motherboard and everything actually within the case 
is fine. However, the screen has been badly affected - it has big glare 
artifacts across more than a quarter of its area, although all the 
pixels seem to be firing OK so maybe the moisture is in a different 
layer or something. The keyboard has 7-8 non-functional keys and I have 
a suspicion it's sending the wrong characters, because I can no longer 
log in - it complains about the password, even though all those keys 
appear to work.

Anyway, it's back in bits in the airing cupboard now. I think it'll take 
some time to be sure of long-term damage...

(kicks self)

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> However, the screen has been badly affected - it has big glare artifacts 
> across more than a quarter of its area, although all the pixels seem to be 
> firing OK so maybe the moisture is in a different layer or something.

Yes, it's pretty unlikely that any moisture got inside the actual LC, or 
even under the polarisers, they are all laminated together with 
moisture-proof seals around the outside.

What probably happened is the beer got between the rear polariser and the 
backlight, there is usually a 100-500 micron air-gap that could easily fill 
with liquid.  Any contamination in this area will show up very obviously on 
the screen.

Cleaning it out will be hard, if you're lucky you could remove the actual 
display panel from the backlight without too much effort (sometimes they are 
stuck down with almost super-glue like adhesives!).  But then the backlight 
will consist of several very thin optical films, which the liquid could have 
got between too.  In theory you could take the backlight apart and clean 
each film thoroughly, but I don't rate your chances of being able to get 
back to a perfect looking screen (this sort of assembly is normally done in 
clean rooms).

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scott wrote:
>> However, the screen has been badly affected - it has big glare 
>> artifacts across more than a quarter of its area, although all the 
>> pixels seem to be firing OK so maybe the moisture is in a different 
>> layer or something.
> 
> Yes, it's pretty unlikely that any moisture got inside the actual LC, or 
> even under the polarisers, they are all laminated together with 
> moisture-proof seals around the outside.
That's a relief.

> What probably happened is the beer got between the rear polariser and 
> the backlight, there is usually a 100-500 micron air-gap that could 
> easily fill with liquid.  Any contamination in this area will show up 
> very obviously on the screen.
Well, I'm hoping that my overkill sloshing of ethanol is the main 
culprit here, and that most of it will evaporate eventually. I've taken 
the trim off the screen which will help, I guess - there are some small 
vents around the edge of the actual screen panel. I'm reluctant to take 
it apart further without good reason because I have zero experience with 
LCDs!

> Cleaning it out will be hard, if you're lucky you could remove the 
> actual display panel from the backlight without too much effort 
> (sometimes they are stuck down with almost super-glue like adhesives!).  
It doesn't look human-dismantle-able, I couldn't see any more screws 
than those that hold it to the plastic case.

> But then the backlight will consist of several very thin optical films, 
> which the liquid could have got between too.  In theory you could take 
> the backlight apart and clean each film thoroughly, but I don't rate 
> your chances of being able to get back to a perfect looking screen (this 
> sort of assembly is normally done in clean rooms).
Are they very delicate? I don't have access to a clean room but we have 
any amount of rubber gloves, sterile dooberys and anti-static wossnames 
in our lab at work.

The real problem is if the films are held together by decent adhesive I 
might break something just taking it apart. This will be a worst-case 
last-ditch option I think!

Thanks for the info

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>> What probably happened is the beer got between the rear polariser and the 
>> backlight, there is usually a 100-500 micron air-gap that could easily 
>> fill with liquid.  Any contamination in this area will show up very 
>> obviously on the screen.
> Well, I'm hoping that my overkill sloshing of ethanol is the main culprit 
> here, and that most of it will evaporate eventually.

It may be a residue of ethanol on the rear polariser, you could try and put 
a few drops on the front of the screen and see if you can see anything once 
it has dried off.  Polarisers are funny things and react weirdly sometimes 
to certain chemicals.

Turn on the screen anyway, it will generate a load of heat which will help 
dry out any left-over moisture.

>> Cleaning it out will be hard, if you're lucky you could remove the actual 
>> display panel from the backlight without too much effort (sometimes they 
>> are stuck down with almost super-glue like adhesives!).
> It doesn't look human-dismantle-able, I couldn't see any more screws than 
> those that hold it to the plastic case.

Yeh, they are not really designed to be taken apart once assembled.  A lot 
of the components are stuck down and "snapped in" rather than screwed.  If 
you don't know the details about the exact model you could easily end up 
breaking something.

> Are they very delicate?

The panel will be made from two sheets of glass stuck together around the 
edge, each sheet of glass is probably between 0.3 and 0.7 mm.  The only real 
weak point is around the edge where there is no polariser attached to 
strengthen the glass - it is really easy to chip or snap off a corner or 
edge of the glass here, especially as this is usually where it is stuck down 
to the backlight.  Once you do that it's the end, because there are 
electrical connections and circuits all around the edge of the glass.

> The real problem is if the films are held together by decent adhesive I 
> might break something just taking it apart. This will be a worst-case 
> last-ditch option I think!

The films aren't usually held together by anything, they just sit in there 
and are constrained from moving by all the other components.  Once you get 
the panel itself off, the films should just lift out one by one (maybe they 
have a small dab of adhesive in one corner to help keep them in position).

The hardest bit is the glue around the outside of the panel that holds it to 
the backlight.  Maybe you have some chemical that can dissolve this 
adhesive, or just go around the outside carefully with a knife (if 
accessible).  Don't put any force on the edge of the glass though, it's the 
weakest point and will chip easily.

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>>> What probably happened is the beer got between the rear polariser and 
>>> the backlight, there is usually a 100-500 micron air-gap that could 
>>> easily fill with liquid.  Any contamination in this area will show up 
>>> very obviously on the screen.
>> Well, I'm hoping that my overkill sloshing of ethanol is the main 
>> culprit here, and that most of it will evaporate eventually.
> 
> It may be a residue of ethanol on the rear polariser, you could try and 
> put a few drops on the front of the screen and see if you can see 
> anything once it has dried off.  Polarisers are funny things and react 
> weirdly sometimes to certain chemicals.
> 
> Turn on the screen anyway, it will generate a load of heat which will 
> help dry out any left-over moisture.
> 

My laptop's screen died after I was caught under heavy rain, carrying it 
in a not-so-waterproof bag...

I never knew exactly what happened, but apparently some water got caught 
in the screen, causing the sort of effect Bill is seeing, I think. At 
first it was working OK but large drops of liquid could be seen, I 
believe they were behind the pixels and just in front of the backlight. 
I thought turning it on would help it dry, and apparently it was an 
error... One day after that the screen would not show anything. Perhaps 
some metallic connector got corroded by the water, I don't know.

The screen can still be turned on (it was a year ago), but now shows 
only squarish clusters of weakly colored pixels. Something hard to 
describe... Anyhow my laptop has became a desktop :-( And traces of the 
water can still be seen.

The interesting thing is that it had one broken pixel that permanently 
appeared red. This is now the only pixel with a definite color ;-)

I don't know exactly how you can solve the problem, but in my experience 
turning it on to make it dry did not help...

-- 
Vincent

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> I thought turning it on would help it dry, and apparently it was an 
> error...

You need to make sure all water (or anything water-based, eg beer) is gone 
before turning it on.  As soon as you get water in anything electronic rip 
the battery out immediately, otherwise the tracks on the circuit boards (and 
the glass if you have an LCD) will start to corrode very quickly.

Only after you have got rid of all the water should you attempt to put the 
battery back in and turn it on.  Using ethanol (as Bill did) is a good way 
to get rid of all the water, my suggestion was to turn it on to encourage 
any remaining ethanol to evaporate.

Sorry if that wasn't clear... I take no responsibility for anyone damaging 
anything :-)

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>> I thought turning it on would help it dry, and apparently it was an 
>> error...
> 
> You need to make sure all water (or anything water-based, eg beer) is 
> gone before turning it on.  As soon as you get water in anything 
> electronic rip the battery out immediately, otherwise the tracks on the 
> circuit boards (and the glass if you have an LCD) will start to corrode 
> very quickly.
> 
> Only after you have got rid of all the water should you attempt to put 
> the battery back in and turn it on.  Using ethanol (as Bill did) is a 
> good way to get rid of all the water, my suggestion was to turn it on to 
> encourage any remaining ethanol to evaporate.
> 
> Sorry if that wasn't clear... I take no responsibility for anyone 
> damaging anything :-)
> 
> 
Well in my case the damage is done and I will only blame myself :-) In 
fact I'm surprised that the screen is the only thing that died in that 
laptop...

I guess what confused me in your previous post was the term "moisture" 
which I associate with water.

That raises another question: how can one be sure that no water is left, 
before turning the screen on? And if liquid can be seen still, how can 
you tell it's ethanol?

-- 
Vincent

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> That raises another question: how can one be sure that no water is left, 
> before turning the screen on? And if liquid can be seen still, how can you 
> tell it's ethanol?

Good point, I assume that Bill has it covered though:

"Well, I'm hoping that my overkill sloshing of ethanol is the main
culprit here,"

I had a look through a few documents here and my suspicion is that the 
ethanol might have done some permanent damage to the polarisers.  Here we 
have to test the polarisers for lots of different things (petrol, diesel, 
sweat, face-cream, cleaning fluids, coffee etc), and one of the tests for 
cleaner fluid (some mixture with ethanol in it) often fails and leaves 
permanent marks on the polariser...

FWIW we use IPA (isopropyl alcohol) for cleaning the polarisers... might be 
worth a shot if you can get to the inside.

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