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 Post subject: Dell C840, can't install from CD, & room fan solution
 Post Posted: Sat Aug 04, 2007 10:33 am 
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Joined: Sat Jun 30, 2007 10:36 am
Posts: 208
Just bought a used Dell Latitude C840 laptop. Tried installing OS from local CD, but it kept stopping at various stages. Cursor still movable but progress bar stopped. No on-screen controls responded. Having erased WinXP, I think HDD was ok but couldn't be sure (it was ok earlier & no problem erasing it, which took close to 28 hours after booting floppy DBAN because of parameters I set, but suggesting HDD was still ok & FDD booted ok). CD/DVD tray wouldn't open by pressing its button (didn't try paper clip). Laptop sitting on top of metal PC tower case, PC in use. Laptop bottom warm, especially on right. Air from inboard fans (which are on right) was warm. CD/DVD drive & FDD both on left. No temperature sensor listed in BIOS. Power button did nothing (didn't know about 4-second hold yet). Only way to end session was to pull out power cord and battery. Waiting an hour, rather than a few minutes, meant new installation attempt would probably go farther before failing again. This being in July, my room was kinda warm; no air conditioning; wasn't using room fan; I'd thrown a wet towel down my back and kept typing.

Solution: Aimed room fan with 18" blade span at medium speed 2' from CD/DVD drive on left of laptop and across laptop with screen lid raised. Propped laptop onto couple rolls of duct tape to expose case bottom for cooling. Waited 1-2 hours, maybe. Took away duct tape rolls (one on right was warm). OS installation quite successful. Explored newly-installed OS quite successfully. Kept fan on. Next morning, repeated installation (replaced OS again). Installation anew quite successful. Explored newer newly-installed OS quite successfully. Using CD/DVD drive after long rest even though laptop in long continuous use (room fan on) is no problem.

Recommendation, if you have similar laptop and symptoms: Take an 18" fan wherever you go.

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Nick


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 Post Posted: Sat Aug 04, 2007 11:35 am 
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Joined: Sun Feb 04, 2007 11:44 am
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That laptop uses a Pentium 4 processor, of which even the so-called mobile versions run extremely hot.

Stuffing the super-hot running P4 into a laptop was a bad idea from day one, and IMHO they should be avoided. Unless of course you like laptops that run so hot they can't actually be used on a lap, and require that you carry fans around. <g>

Even for used laptops I only recommend those using Pentium III, Pentium M, Core or Core 2 processors, as those are the "coolest" chips around. Scott.


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 Post Posted: Sat Aug 04, 2007 2:19 pm 
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Maybe I'll carry around 6-sided pencils that don't roll, and lift the laptop off the table. Or books, under the corners. Or duct tape rolls. Or frozen ice-cream pops -- oh, wait a minute. Any cooks need thawing service?

Thanx.

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Nick


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 Post Posted: Sat Aug 04, 2007 4:23 pm 
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Joined: Sun Feb 04, 2007 11:59 am
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I've got a couple of those laptops and they sure do run hot. I am not surprised you ran into overheating issues with a high room temp. They are just bad laptops!


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 Post Posted: Sat Aug 18, 2007 10:37 am 
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To be technical, when the heat-related CD malfunction was going on, the laptop wasn't on its feet (because it was resting on something smaller). The direct rest cost an airspace of about 1/16". But before any company rep blames me, let's note that use on a lap also costs that airspace. Legs fill it up.

Also, it was resting on metal, a heat conductor (albeit of a CPU tower but the laptop was over the tower's CD reader, not in use). The average human lap is an insulator, which is why that scorching you feel stays local, helping to cook the laptop processor even more. Ooph.

I'm planning to rig up a spare internal desktop fan (maybe 3") to USB to use externally at public places, when my laptop is running off AC (not battery), maybe wrapping mesh to keep fingers and debris out. Companies already sell things like this, so the load will probably be ok.

This is a bit like being sick is good for the economy, because healthy people don't visit doctors but sick people do, raising our GNP. Intel's or Dell's design decision is great for the accessory industry.

I don't have the time to dig into the engineering specs, but maybe someone knows if the problem is with Intel in specifying too little compensatory cooling, with Dell and maybe other manufacturers in not implementing it adequately, or both. I do notice that when installing from CD fails, the flashing CD LED goes dark and the disc is warm to the touch, even though the tray is on the left, away from the processor. If that's from the combination of both reader-local heat and processor heat, the heat travels too well and cooling is too weak.

It's annoying to have to do all this, but the laptop will live.

Thanx.

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Nick


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 Post Posted: Sat Aug 18, 2007 11:03 am 
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If you haven't opened that thing up and cleaned it out, you should.

I recommend you disassemble the base down to the motherboard, remove all socketed devices and unplug anything that is plugged in. This of course includes the processor.

Blow out everything with compressed air, esp. the CPU fans, cooling ducts, vents, etc. Make sure you hold the fans stationary while blasting (do not let them spin from the compressed air stream).

Reassemble everything, possibly plugging, unplugging and replugging each connector once or twice to wipe the contacts.

Clean the CPU and heatsink of all previous thermal interface material (TIM). Then reinstall the CPU, apply the thinnest layer of fresh thermal grease that will cover the processor die (or heat spreader if one is covering the die).

Test the system before buttoning it up to be sure that the fans are spinning properly, replace them if they seem worn or running slow.

This should do wonders for an old, overheating laptop. Scott.


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