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My laptop has had a problem recently. When I flicked the power button on, it won't come on, the lights won't get turned up, etc. I had checked the wiring connection and that had no problem. I had to get it repaired, but a few days later the same thing happened. And I've just received it after getting it repaired a 2nd time.

The repair guy told me that I'm leaving the laptop on for too long and the temperature of the room is too hot. Could that be it, or also that I need a stabilizer to stabilize the electric power? Or that I need to unplug the power socket when the battery is 100% charged so it doesn't get over charged?

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4 Answers 4

up vote 2 down vote accepted

Yes, laptops can have a thermal cut-out (or at least my old Athlon XP system does). Usually this will manifest itself as the laptop suddenly turning off without warning, as opposed to refusing to power on altogether (you don't say if it refuses to power on from "cold" i.e. not being used for a while, or not).

Even if it has a thermal cut-out, you should still see power lights on the machine (a/c power connected) - it's just that it will refuse to turn on.

If it's not thermal, then the most likely would be either the a/c power supply or the battery. You'll need to try combinations of running the machine just on battery, just on a/c (take the battery out completely), with battery charging etc. You should be able to narrow it down and replace the bit that's broken - ebay would be the best bet, especially for a power adapter.


More info:

Thermal

When my laptop's thermal protection steps in it's pretty obvious. Feel under the laptop roughly where the cpu is - in the middle towards the back - if it's a thermal issue it will be really hot to the touch. You need to promote airflow - you can try clearing the vents/grills ( a blast of compressed air or the attentions of your vacuum nozzle will do the trick). Otherwise, if you're using it on your lap, try to place it on something flat, like a tray, rather than on a cushion / pillow which may be blocking the vents. If it does cut out, you just have to wait for it to cool - you can try closing the lid and leaving it upside down which may let some heat dissipate faster.

Power

You've said that it's infact refusing to power on from cold, which means it's probably not thermal (unless your ambient temperature is > 120F). If you have no battery, just A/C, you should still see the A/C light even when the machine is off. No lights imply a dodgy power supply.

Make sure the cables on the supply (plug to transformer, transformer to laptop connector) are good with no obvious signs of damage, especially around the ends of the cable (where it joins the plug, transformer, connector) - this can flex and break over time, especially if you wind it up a lot and stuff it in a bag. Also check the power socket on the laptop - make sure the central pin isn't loose - again these can fail over time.

Ebay would be the best source of a power supply, especially for an older machine - you should be able to get a generic replacement: you need to check the output of the transformer and that the connector is compatible (good sellers will list what machines it fits). If you find the pin in the power socket on the laptop itself is broken, then this is much harder to fix - you can source them from radio shack (us) / maplins (uk) but it means complete disassembly and soldering on of the new fitting - not easy.

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Beat me by seconds! –  JFV Jul 18 '09 at 16:49
    
The first time this happened, at first even the power light wont go off, but after i kept it pressed for a while then the power light would go blue but it wont turn on. The 2nd time if i used battery then the power light would show, but using just a/c with battery not connected wont make the light go on. If its the thermal cut out feature, how can I overcome it, i.e the next time this happens how can i make the laptop get turned on? –  Click Upvote Jul 19 '09 at 23:29
    
Also, both times it refused to get powered up after I had left it turned off for a while, so likely it was cold at the time –  Click Upvote Jul 19 '09 at 23:31
    
Added some more information –  iAn Jul 20 '09 at 1:46

Your laptop properly has an anti-overheat feature, but that should only prevent it from booting for at most 5 mins. You didn't tag the question with desert, so I assume your room is less than 40c, which means that overheating should not cause any permanent problems (it shouldn't cause temporary problems either, but fans can gather dust).

So my solution would be to run it on the battery, as this will eliminate power fluctuations to test if that makes any difference. You could also try to run it through an UPS, but unless you are getting electricity from a homemade generator I sincerely doubt that should be an issue.

Any laptop should be smart enough to stop charging the battery once it is fully charged so that is unlikely to be an issue.

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I have heard that for battery long life, one should unplug the power once the battery level reaches 100%.

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Maybe in rally old (decades old models). However anything from the last 20 years will stop charging once the battery is full. –  Hennes Sep 11 '13 at 16:42

I have heard of laptops that have problems (later in life) when they are plugged in with the battery in it. Try to take the battery out and run directly from the power to see if you'll be able to power on without any issues. Or do vice-versa, run only on battery for a while to see if there are any issues.

-JFV

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