[Kerygma99]

If I have my Pismo asleep in a laptop bag, say a Targus, and I have to spend 20 or 30 minutes at a time walking in sub-zero temperatures (I live in Canada), is there any potential for damage to the unit (I'm thinking, obviously, of the screen)? Any idea?

P.S. btw, can someone tell me whether or not the announcement of a G4 'book is confirmed for January? Or is it just a rumor with a varying degree of likelihood? Thanks...

Kerygma

[tooki]

Well, if the computer gets cold, you will just have to let it acclimate (for over an hour, to prevent condensation) before turning it on. I'd get a very insulated bag for it.

As for PB G4 rumors, this has been discussed a lot, and a search will yield many results. However, NOBODY knows what Apple's plans are (not even many Apple employees), since Apple has a very strict policy of keeping everything top-secret until it is released. Wait two weeks till Macworld.

tooki

I wouldn't be as concerned about condensation as I would about the liquid crystals in your display freezing. I'm no expert on the effects of cold on liquid crystal, but sometimes my calculator doesn't display right on cold, frosty mornings.
Apple says the minimum storage temperature is 40 degrees, so my recommendation would be to get one of those keychain thermometers, toss it in with your powerbook in the same compartment and see if it makes it below 40 at the end of your walk. (Post your findings; I'd be interested to know!)

Oh, about that new powerbook, I think the fact that apple seems to be clearing the channels (the drastic price cuts on the pismo effective today) would be a good indication that they're trying to empty their warehouses of soon-to-be outdated product! Wooohooo mercury!

[tooki]

Originally posted by Aykew:
I wouldn't be as concerned about condensation as I would about the liquid crystals in your display freezing. I'm no expert on the effects of cold on liquid crystal, but sometimes my calculator doesn't display right on cold, frosty mornings.

It's perfectly normal for LCDs to get weird at low temperatures. And if that did happen, it wouldn't take too long to warm back up, and the changes are not permanent -- the display will recover once it warms up. I'd be MUCH more concerned with condensation, which could cause anything from crashes to permanent hard disk damage (read: data is gone, drive is fried) to short circuits.

Think about it: if the thing is cold, water vapor will condense on the unit (unless you are in a room with 0% humidity). The water droplets form on the hard disk platter (hard drives are NOT hermetically sealed), causing a head crash, which is a death blow to the drive. Water droplets cause shorts on the memory chips, causing memory corruption, and hence crashes. While I am certainly painting a grim picture, those are the reasons why professional A/V gear (which gets schlepped around a lot) has condensation sensors that prevent the units from turning on if there is condensation (in fact, most home VCRs have that function, and will display an error on the TV screen if that happens).

Seriously, take your time letting the machine acclimate. You can do one thing though: before letting the thing get cold, put it in a huge ziploc bag (something that you can make airtight), then go on your walk, and then when you get back, you can use it, but just don't open the bag until later.

tooki

Apple's own specs specify that you can store the unit in temperatures as low as -47� C, but it shouldn't be operated at temperatures below 10� C. Figure that ideally you have to give it enough warm up time to allow the internal components to reach 10� before powering up.

-Vince

[israces]

Maybe you want to rethink the ziploc bag idea??
The problem is that cold air does not hold as much moisture as does warm. Therefore, sealing the PB in a warm environment that will then cool will be more harmful than good. For example, say at 68 degrees the humidity is 40% and at 0 degrees its only 5%. Sealing your PB in a bag at room temp also traps the moisture inside. Now drop the temp to 0 and that moisture has nowhere else to go but to condense inside the bag. Plus, once you take your wet PB out of the bag, you still have to think about condensation from the contact between the cold PB and the warm room air. Of course, were only talking a about a few drops here and not a gallon of water or anything.
The only way to avoid condensation is to somehow keep the temp of the PB in the bag at the temp you are going to be using it at.
In other news, I used to trek across campus for about 30 min in sub zero temps with my PB in a backpack. Never really let it warm up and haven't had any problems. The display looks a little slow for a few minutes but that's about it. I'd say don't worry about it too much.

[Zwilnik]

I always seem to be plugging these things, but a boblbee backpack might be a good idea if you have to carry your powerbook in extreme conditions a lot (I use mine to carry my iBook around in the UK, where the total waterproofing comes in quite handy with our rain).
The boblbee is watertight, armoured (it's an ABS shell on an aluminium zinc alloy frame) and more importantly, carries the computer directly on the back, where it is most protected (and also the warmest, until someone invents a tummy pack, which would be excellent for powerbooks in really cold climates). These things are *tough* and suprisingly light.
http://www.boblbee.com

no, I don't work for them, I just use one (despite it being difficult to get them in the UK).

btw. I was sure I read somewhere that once an LCD freezes solid, it's permanently damaged, but I'll go away and find some research to back that info up first. later...

[Zwilnik]

nope, I couldn't find anything relevant about the freezing LCD (I was sure it was on these forums). It must have been to do with when the LCD goes below the storage temperature. Generally though I'd make sure it's carried in a bag with plenty of insulation and avoid using it until it's warmed up to room temperature.

NiCad and NiMH rechargeable batteries fare very badly when frozen (I've destroyed more than one this way, leaving them in a car overnight when on a ski trip for instance). However, I don't know whether the newer Lithium Ion batteries used in current Powerbooks suffer the same effect - probably not, since you're supposed to be able to store the thing at such a low temperature. This is the only thing that would concern me personally.

I imagine luggage can also get pretty cold in the unheated luggage compartment of a high-altitude airplane flight, though most people probably carry their computer (and batteries) with them.

[tooki]

Well, contrary to popular belief, most cargo holds nowadays are climatized, since airlines now routinely carry animals, exotic plants and out-of-season vegetables, and other such sensitive freight.

tooki

I did have some problems with my PowerBook and the cold. I used to live in Ohio and a couple occasions, I left it in the car overnight (in the gargage, no less, so it wasn't THAT cold). Every time that I did that, and went to use it again, the screen cracked (about a one inch bar that was only white)...it had the same effect if I let it warm up in the house before using it.

This was a PowerBook 180c, so it was back in the day. I doubt LCD's have changed much since then, but Apple's warranty did cover the screen (I accidently forgot to tell them about leaving it in my car)...although, I'm not sure if they would still cover it.

In my opinion, I would protect your PowerBook from the cold (not to mention yourself!)...

[israces]

For some reason I remember being told to use Li ion batteries in the extreme cold as opposed to NiMH or NiCd. Can't remember why exactly.

[stardoc]

I suspect that if you do the thermometer-in-your-bag test during a 30 minute walkabout, you will find that the temperature in the bag has not fallen below 10 C. My Targus case has (thin) foam on all sides which serves as a significant thermal barrier for short periods of time. The powerbook's case then also serves as additional insulation for the PB's guts--not much, but we're talking about a real short time interval here.

With regard to condensation, unless you are in a humidified building (home or apt, but often not school/work) the humidity is probably very low since the air has been heated up from the ambient air. So there's not likely to be much condensation forming while you are out. Upon your return, if the PB is cold you can wait, but 30 minutes......

Here in New England, I just carry my PB in a nylon bag for 10 minutes and it barely has a chance to get cool.

Hi I currently use my PB outside frequently. I'm in Rochester, NY its subzero this time of year lets say oh -5c. I use it at the bus stop not waste working time. No problems cold/hot/cold it takes it all in stride. keeps my fingers warm.
as a neato side note you can get newer gauges and watch the tempature drop on your processor as you use it.
Nope ,it won't an overclock and extra.

[AlbertWu]

Leave it on.

That'll keep it warm!
'specially if you get a mercury.

------------------
Albert Wu <- No life.
http://web.harker.org/

24/7 Cell phone use can not kill you. I am an example.

[CMYKid]

>Every time that I did that, and went to use it again, the screen cracked

every time? um...exactly how many times DID ya hafta do this before ya quit doin it, hmm 8-)

:ryan
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