I have a Dell Latitude C640 laptop. It shuts off all the time and can usually only get windows loaded and it’ll shut right off
Hi, I have a Dell Latitude C640. It shuts off all the time and can usually only get windows loaded and it’ll shut right off, then it will turn on and turn off right away at boot. I’m very familiar with taking these apart and when this first occurred I suspected a clogged cooling system. So I checked, and it was clean as a whistle… hmmmm…so I’ve been looking for anything out of the ordinary on the motherboard but everything is tight and looks clean. Even took the LCD apart to make sure there weren’t any loose connections. So if you could give me any insight on this it would be a great help! The only thing that “SOUNDS” suspicious to me, is that sometimes I can HEAR the power when I plug it in, a very faint high pitch ringing noise…. so then I figured well if its the plug technically it should still run fine off the battery, but it does the exact same thing. I’m also suspecting that maybe my fans aren’t running fast enough?? Or maybe I need some new thermal grease on the CPU??? HELP!!
Yeah, looks like an overheating problem. By the way, have you checked if the fan spins at all? May be it stuck and causing this high pitch noise?
I would probably remove the hard drive and boot the laptop from a Knoppix CD. Knoppix is a live Linux CD and it will boot your laptop to a Windows like environment. You don’t need the hard drive to boot the laptop with Knoppix, only the DVD/CD drive. If the laptop boots fine and doesn’t shutdown, then something is wrong with the hard drive or with the operating system on it.
Also I would test the memory module. You can run Memtest 86+ and see if the memory fails the test. It’s possible, that the memory works fine for a while when it’s cold, as soon as it warm up it fails. That’s why your laptop works fine for some time, and then just shuts down when you restart it. If the laptop doesn’t run long enough to finish up the memory test, then try to replace the memory if you can find any test module.
Of course, I would try to reseat all connectors inside the laptop. Any loose connection might cause this problem.
May 19th, 2007 at 8:51 pm
If the fan is working and the cpu is not reaching too high temps (above 80C) it may be that the hard drive is overheating. Using mobile meter my laptop shows moderate cpu temp at 60C but the hard drive slowly rises from under 40C to 60C and shuts down. At first it takes about an hour to heat up but then shuts down quickly if I don’t get it time too cool. I can’t seem to find a solution to keep the drive from overheating, and it picks up temperature even without reading/writing anything. Any ideas would be great.
April 1st, 2007 at 12:12 am
Sounds like a class action suit is in order
March 31st, 2007 at 11:55 pm
I have the same pre-mature shutdown problem with the Dell Latitude C640 and was told it was my TMobile Wireless Internet card that must have a short in it. But, the card works fine in other laptops. I am going to return this pc.
February 28th, 2007 at 9:30 am
I’ve had my C640 (2ghz, 1G of Ram, 40 gb)for almost 3,5 years and never got a problem with it. until recently i started to get the same problem, humming noise when i put the power plug in and tries to start, load windows for a couple of seconds and then shuts down. same behavior when on Battery mode as well. i was able to do some circuit test to see where the problem, and i’m sure it’s one of the capacitors responsible for power distribution. You can change the capacitor but it’s hard to find. I changed the Motherboard and it’s back on track running smoothly.
February 21st, 2007 at 6:57 pm
Thomas,
It’s hard to guess what’s going on. Do you get any image on the screen when you turn on the computer? Can you access the BIOS setup screen at all? If you can, leave the computer with the BIOS setup screen for a while and see if it still shuts down.
I’m just trying to narrow down the problem.
February 20th, 2007 at 4:25 pm
I recently got a QBook 8589 laptop off ebay (I would rather say it is a desktop, using desktop Intel Celeron D 330 2.66GHZ and desktop ram, but it looks like laptop and a 2.5inch hdd). It shut down itself completely after turning on no more than 1min(the screen display fine). after research on this site, I’ve clean one cpu fan/heatsink and one graphics fan–>and put new thermal grease–>put everything back, two fans running fine(noisy but gives strong air, after a 10seconds, it gives warm air, so i think the fan/heatsink are doing fine), the problem still the same, when it shut itself off, I use my finger to touch the cpu heatsink, it is pretty hot. It is because the laptop have a faulty CPU or a faulty video card or faulty memory? If it is just cpu, i can change one but if it is video card I can’t do anything. I will try to get a desktop memory from my friend’s dekstop, but I don’t think it is the memory problem.
Do you have any idea why this happens? Thanks in advance.
January 26th, 2007 at 3:04 pm
after using my latitude c640 for 4 year I upgraded memory from 256 to 512 and upgraded the bios from A03 to A10, now I too can just manage to log onto windows before it shuts down, have swapped memory, but still having problem, think it must be related to bios update…D’oh!
January 19th, 2007 at 9:06 pm
I too have a C640 that died from heat exhaustion. System is fried but I was able to get my data off by setting the system on blocks of blue ice
January 17th, 2007 at 10:04 pm
Hi
Suggestion for all fried (non booting or random shutdowns) lattitude c640′s. It is probably the motherboard- customer service at dell immediately reccommends replacing it when i told them my problem. reccomended fix? – buy a new motherboard on ebay- only about $150, and not too hard to install- use the dell service manual- available at the dell support site.
good luck!
January 11th, 2007 at 9:09 pm
Hi
I have an Averatec 6100 laptop with a similar problem. Whenever i run a memory consuming process – for example downloading music, virus scan , windows update, or even play music with windows media player or winamp – or whenever i have simultaneous applications running, the laptop slows down considerably and shuts down unexpectedly with no error. If i leave the laptop on for several hours without running any memory consuming program then it does not shut down.
From the Laptop Freak: the solution has been published here.
January 10th, 2007 at 8:33 pm
Ron,
Probably it’s time to reinstall the operating system.
January 10th, 2007 at 9:11 am
Hi
I have a Toshiba 410 laptop and there are times when I try to shut down but it takes few minutes before it shuts down. It happens about 50% of the times when I try to shut down. Once I choose shut down nothing seems to happen and I am able to go to the Turn Off Computer options again and choose again shut down, but it doesn’t make it any faster. When it’s slow shutting down, it takes about 3 minutes. There aren’t programs that I leave open before shut down.
Any suggestion what I can try to do?
Thanks
Ron
January 1st, 2007 at 1:39 pm
I am now experiencing this problem with the C640. Last time i used the laptop was two months ago and it worked fine. Now it powers down after 30 minutes after first plugging in and then every few minutes thereafter. Certainly seems to be heat related but more importantly, the power supply light on the laptop goes off as well.
I suspect that this has nothing to do with the CPU but rather a failed capacitor on the DC input circuit. Can anyone confirm?
December 25th, 2006 at 6:00 pm
Hi I also have this sudden switching off issue with my dell C640. It turns on then at seemingly random time’s 10sec’s to 30 min’s it just turns off (like I have just removed the battery and mains at the same time). so far this eve it’s been working for nearly 3 hours couple of probs earlier on, then it behaved. Something however I have noticed is that the system has started to forget the date and time.
Does anyone think this may be related to the power off problem? i.e. system will not work unless it has some settings to read etc. Although admittedly if the thing has been working for 30 mins, I would normally have expected the system to carry on regardless of BIOS battery status. I figure it may be worth trying a new bios battery but not much else. Unless I hear otherwise
December 14th, 2006 at 8:28 pm
Hi, I replaced the heatsink fan in the latitude c640 (was constantly shutting down and I noticed that the fan was not coming on) and now when I hit the power but all I get is the above mentioned high pitched noise. Does this mean the MB has now gone bad? If so can you recommend a good place to purchase an inexpensive replacement? Thanks in advance, J.
December 11th, 2006 at 11:49 am
I work in a callcenter that uses nothing but Dell computers. First, let me tell you, that your when your Latitude cops attitude like that, it’s 9 times out of 10 the motherboard. I know this because we had at one time about 150 C640′s. Out of those 150, 65 of them died in a similar manner. They sort of work their way to not working, starts cutting off at random more and more often until it won’t work at all. What I found that works, at least as a temp fix, unplug the power, remove the battery, push the power button down for 10 seconds. Then replace the battery and turn it on, then replace the a/c power. It will come back on for a bit but eventually turn off. All the techs I spoke with say it’s a power supply issue on the motherboard. The high-pitched noise you hear are bad capacitors, not fans.
Powers supplies seem to be an issue for Dell. We have 175 GX270 models here in the building. Each one has had it’s power supply replaced. Some have had it done 2 or 3 times in the last year. Cheap parts. However, for those of you who have power supply issues with your dell or other branded desktop, I recommend http://www.power-on.com. They carry an aftermarket version for desktops like Dells and are reasonable on the prices.
November 21st, 2006 at 7:42 am
I know what the problem is with the Dell C640′s. I worked for a corp. and had to rebuild about 40 of them before we armwrestled Dell into replacing all of them. The problem as noted above is overheating. Once you start having the problem often it is too late. The processor is done. The processor, heatsink, thermal grease, and fan need to be replaced. I actually have one at home that is now starting to have this issue and will have to find the parts to get back to running shape. Hope this helps!
November 9th, 2006 at 12:02 am
Unluckely I had already tried everything you mentioned: moving and changing memory module, reseating CPU… I even chaged both fans.
Laptop (in this case MB + CPU + Memory) seems to turn on only when it decides to do it.
Probably there’s a faulty circuit or welding on the MB: sometimes, moving and stretching the MB makes it to work, even for a brief time.
I tried to find a rule (twisting & stretching the MB, applying pressure on several points of it) but I found none.
I go on trying…
November 8th, 2006 at 6:44 pm
Gico,
That’s a good idea to troubleshoot a laptop this way if nothing else left. For this test you’ll need only three basic components: motherboard, CPU and memory. You didn’t mention memory, so make sure to test it with a memory module. Test the system with an external monitor. If all three components are in a good shape, you should get a video output on the external screen.
If you disassembled the laptop down to these three main components and still cannot get any video on the external monitor, then most likely one of the components is bad or not seated properly. Try moving the memory module into another slot. Use a test memory stick if you have it. Try reseating the CPU. If still nothing, then most likely that’s a bad board. From my experience laptop CPU failures are rare, motherboards fail much more often.
November 8th, 2006 at 8:38 am
I’ve just made some experiments.
I disassembled toatally the laptop again:
now I have only the motherboard and the CPU but when I press the start-up button NOTHING still appens.
Only few times (in many tries) the power-on led lit.
I’m afraid it’s something with the MB.
November 8th, 2006 at 2:23 am
Hi, I have the same problem with a Dell Latitude C640:
I can’t keep it turned on: sometimes it turns off during boot, sometimes after loading windows. In any case it doesn’t last more than few minutes. After some tries it does not turn on anymore.
After I disassembled it TOTALLY (and assembled it again) it started working well, but now the problem is again.
Probably there’s something wrong with some component, but wich one?
Gico
November 6th, 2006 at 11:12 pm
Alex,
Most likely your laptop shuts down because it overheats.
November 6th, 2006 at 2:43 pm
I have the same prob with a Toshiba Satellite – maybe increased fan volume and then abruptly shuts down.
1. Is it possible this cd be caused by spyware or any other kind of virus?
2. I am working in Microsoft word. Only half the time or so I get autorecovery. Is it possible to ensure the file I am working on has autorecovery every time since half the time I am losing work- v annoying!
Thank you for your time,
Alex
October 19th, 2006 at 12:50 pm
Hi,
I experience similar problem with my Laptop. Its a Presario 700 series. The fan had went out on it. The keys above the cpu would get so hot you could hardley touch but it never shut off. I never let run more than maybe 5 minutes. I replaced the Cpu fan and the other fan. Now, when i try to boot it up it shuts off no shutdown or anything. (I am having to restore harddrive as well) Once or twice I get into the restore program and it will start to do restore then shutoff. Is this an overheating problem or do I need look else where?
Thanks
October 3rd, 2006 at 6:30 pm
I think the fan works OK since after startup, I exercise the CPU to see if the fan will kick on, which it does, then I relax it and it eventually gets to a state where the fan goes off. I tried this a few times and it appears to follow what one expects.
I also tried the I8KfanGUI program on the web and it measured the CPU temp and the peak was like 60 something. This laptop apparently cannot monitor the memory temp so I cant tell if the heat problem resides there. I also am not continuously looking at the fan GUI results as sometimes the machine can stay up for hours. It’s too bad that a running log cannot be kept with fanGUI to help in debug. If so, I could tell what the final CPU temp was before shutting off
October 3rd, 2006 at 1:45 pm
Susan,
You mentioned that the fan runs fine. Usually the cooling fan starts as soon as you turn on the laptop, then it turns off and turns on again when the CPU is hot. Does your fan turn on prior to the abrupt shutdown? May be the fan doesn’t work properly or the thermal sensors have failed?
Just recently I repaired a laptop with a similar problem. Here’s what I experienced: the fan spins only on the laptop startup, then turns off and never come back again. As a result, the laptop shuts down by itself after 5-10 minutes. I had to replace the motherboard.
October 3rd, 2006 at 9:15 am
That was also tried, the old thermal conductive tape was removed and a new piece was applied, (the really good stuff too, like $400-500 a roll). The surfaces
were carefully cleaned with alcohol. The laptop is like 4-5 years old, but prior to just a few weeks ago, it ran fine and often was plugged in for days straight without incident.
October 2nd, 2006 at 9:25 pm
Susan,
Even though the heatsink is clean and the fan is running, the problem still could be related to overheating. If the laptop is a few years old, it’s possible that thermal grease dried out and has to be reapplied.
October 2nd, 2006 at 4:48 pm
I have this same problem. I have tried the following to no avail. Most of the time, I get about 20-40
minutes before the abrupt shutdown. Any more ideas?
1. blew out dust with compressed air (not really any)
2. reformatted hard drive
3. new hard drive (to see if it was the hard drive)
4. boot to bios screen (to see if it was windows)
5. made sure fan was clean and running
6. made sure all connections are tight
July 18th, 2006 at 10:13 am
Dear Dell Customer,
I read your post from July 9 regarding your Latitude C640. If you would like to contact me directly regarding any outstanding issues, I will be happy to assist in any way possible. You can reach me at the email below. I look forward to hearing from you. If you would simply like to provide feedback, you are welcome to do so, as well.
Regards,
Kris
Customer_Advocate@dell.com