Laptop randomly loses power

vbnet3d · 08-01-2008, 07:49 AM

Model: Dell Latitude C840

The laptop often completely loses power (i.e. no lights) at random times. It does not seem to matter if it is running on battery or plugged in. It sometimes cuts off when the computer is moved, but it happens when the machine is just sitting there idle too.

I have checked for overheating, but the laptop seems to be running pretty cool.

Sometimes, we get an error indicating that half of the memory (256 out of 512) is inaccessible. Could issue this be related?

This was a used machine when we bought it, but seemed to be in good condition.

**TriggerFinger** · 08-01-2008, 08:53 AM

If you have doubts on the RAM, run Memtest86+. Run it overnight or you can test each module individually for like 2 passes each.

vbnet3d · 08-03-2008, 05:48 AM

The main issue is the loss of power... The RAM usually only fails right after a power loss. I thought it might be related.

Could a bad motherboard cause this issue? I thought about chip creep at first, but can it cause the computer to lose power?

**TriggerFinger** · 08-03-2008, 07:12 AM

Run the following:

Run Memtest86+. Run this overnight.
Run HDD diagnostic to test your drive
Check connection on the DC power jack (try to wiggle the cord and see if it shuts OFF.
Run SpeedFan or NHC to check your temps. Observe and note down temps.

Post back what happens after each test. Thanks.

panseluta · 02-27-2009, 01:13 PM

It's a little late for this answer but here it is:

when your processor is overheating you can lose power without any warnings. you can start the computer after that and lose power again in a few minutes. in this case you have to clean the processor (also to replace the paste) and clean the fan.

In your case you lose power randomly wich has nothing to do with overheating or memory or HDD.

It's a malfunctional AC Adapter!
That little thing made me waste one night trying all kinds of tests with no result.

08-01-2008, 07:49 AM	#1 (permalink)
vbnet3d Registered User Join Date: Aug 2008 Posts: 2 OS: XP Pro. SP2	Laptop randomly loses power Model: Dell Latitude C840 The laptop often completely loses power (i.e. no lights) at random times. It does not seem to matter if it is running on battery or plugged in. It sometimes cuts off when the computer is moved, but it happens when the machine is just sitting there idle too. I have checked for overheating, but the laptop seems to be running pretty cool. Sometimes, we get an error indicating that half of the memory (256 out of 512) is inaccessible. Could issue this be related? This was a used machine when we bought it, but seemed to be in good condition.

08-01-2008, 08:53 AM	#2 (permalink)
TriggerFinger Moderator Hardware Team Join Date: Jan 2008 Location: USA Posts: 11,149 OS: Windows 7 Beta, Vista SP1, XP SP3, PCLinuxOS2007	Re: Laptop randomly loses power If you have doubts on the RAM, run Memtest86+. Run it overnight or you can test each module individually for like 2 passes each. __________________ DBAN - Memtest86+ - BartPE - Linux LiveCD - ImgBurn - HDD Diags - Everest HOW TO BURN AN ISO FILE

08-03-2008, 05:48 AM	#3 (permalink)
vbnet3d Registered User Join Date: Aug 2008 Posts: 2 OS: XP Pro. SP2	Re: Laptop randomly loses power The main issue is the loss of power... The RAM usually only fails right after a power loss. I thought it might be related. Could a bad motherboard cause this issue? I thought about chip creep at first, but can it cause the computer to lose power?

08-03-2008, 07:12 AM	#4 (permalink)
TriggerFinger Moderator Hardware Team Join Date: Jan 2008 Location: USA Posts: 11,149 OS: Windows 7 Beta, Vista SP1, XP SP3, PCLinuxOS2007	Re: Laptop randomly loses power Run the following: Run Memtest86+. Run this overnight. Run HDD diagnostic to test your drive Check connection on the DC power jack (try to wiggle the cord and see if it shuts OFF. Run SpeedFan or NHC to check your temps. Observe and note down temps. Post back what happens after each test. Thanks. __________________ DBAN - Memtest86+ - BartPE - Linux LiveCD - ImgBurn - HDD Diags - Everest HOW TO BURN AN ISO FILE

02-27-2009, 01:13 PM	#5 (permalink)
panseluta Registered User Join Date: Feb 2009 Posts: 1 OS: xp sp2	Re: Laptop randomly loses power It's a little late for this answer but here it is: when your processor is overheating you can lose power without any warnings. you can start the computer after that and lose power again in a few minutes. in this case you have to clean the processor (also to replace the paste) and clean the fan. In your case you lose power randomly wich has nothing to do with overheating or memory or HDD. It's a malfunctional AC Adapter! That little thing made me waste one night trying all kinds of tests with no result.