Cleaned laptop fan, now it shuts down after a few minutes

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DragonQ

Limp Gawd
Joined
Mar 3, 2007
Messages
351
My few-years-old laptop was running hot and the fan was on all the time, even when idle. CPU temps were around 70 °C when idle too. So I decided to take it apart and clean the fan and exhaust holes with compressed air. I did that today, put it back together and booted it. First thing I noticed was that the fan noise is no longer steady but pulsating. Not sure what that means. Then, after a few minutes, the laptop shut down. The only thing I know of that would cause this is automatic shutdown based on overheating CPUs, but I was monitoring CPU temperatures and they didn't go above 55 °C. I tried booting to the BIOS but there's no fan/temperature information (stupid Dell). It also shutdown after a few minutes in the BIOS.

What have I done here? Have I destroyed my laptop with compressed air? I didn't remove the fan or anything else for that matter so I can't see it being a loose cable or anything.
 
Sounds like you may have damaged the fan, or loosened up a heatsink... You're probably gonna have to go back in. :(
 
Well that's not a problem since I didn't put the screws back in. The problem is, I don't even know where the CPU is. I assume it's under the only fan? Is it possible the compressed air damaged the thermal paste somehow?

What I don't get is that surely the CPU temperature would've shown as very high if the CPU is overheating?
 
Another possibility is that when you used the compressed air you may have simply clumped up all the dust particles together, forcing the fan to seize up.

Take a closer look, if that's indeed what happened you may have to find some more creative ways to clean it and dig up the junk to say the least.
 
DragonQ said:
Well that's not a problem since I didn't put the screws back in. The problem is, I don't even know where the CPU is. I assume it's under the only fan? Is it possible the compressed air damaged the thermal paste somehow?
Click to expand...

What model laptop is it?
 
I also wonder if you may have spun the fan faster than it was designed to run causing the bearings to fail.
 
Blowing compressed air on a fan and spinning it opposite to its normal rotation (or spinning it at a higher than normal RPM) can damage the bearings. Make sure the fan is spinning freely without much resistance.

Also, the mobo may not like the fact the fan isn't spinning and is shutting itself down as a result, thinking it's in danger of overheating.

You may have just simply dislodged some large collections of dust that are now jammed up somewhere causing some component to overheat. But if you don't have a GPU and your CPU stays around 55 like you said, then that's unlikely.
 
It has no separate GPU, just the on-board one. It's an Intel Core i5-430M and the laptop is a Dell Vostro 3500. I've attached photos of what the fan looks like. It seems the most promising hypothesis is that I broke the fan by spinning it too fast and the laptop shuts down because the fan speed isn't high enough. I can't see any way to remove it though, let alone replace it.

http://www.aotplaza.com/Files/HardForum/Vostro 3500 Fan 1.jpg
http://www.aotplaza.com/Files/HardForum/Vostro 3500 Fan 2.jpg

I just had a look at the service manual. The CPU isn't located anywhere near the fan so I definitely haven't broken that. Looks like I may have to replace the fan. Looking at the steps in the service manual, pretty much everything needs removing before I can get to it, including the monitor. I should be able to do it myself, although I've never done this kind of thing with a laptop before! Might have to apply new thermal paste but I have plenty.
 
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DragonQ said:
It has no separate GPU, just the on-board one. It's an Intel Core i5-430M and the laptop is a Dell Vostro 3500. I've attached photos of what the fan looks like. It seems the most promising hypothesis is that I broke the fan by spinning it too fast and the laptop shuts down because the fan speed isn't high enough. I can't see any way to remove it though, let alone replace it.

http://www.aotplaza.com/Files/HardForum/Vostro 3500 Fan 1.jpg
http://www.aotplaza.com/Files/HardForum/Vostro 3500 Fan 2.jpg

I just had a look at the service manual. The CPU isn't located anywhere near the fan so I definitely haven't broken that. Looks like I may have to replace the fan. Looking at the steps in the service manual, pretty much everything needs removing before I can get to it, including the monitor. I should be able to do it myself, although I've never done this kind of thing with a laptop before! Might have to apply new thermal paste but I have plenty.
Click to expand...

The fan is in a slot-style shroud/housing. The housing and/or the fan itself is removable. You may have to go in from the other side of the laptop or remove components like the motherboard or keyboard to get access to the fasteners that hold the shroud & the fan in, or you may be able to get at the fan itself. On the sticker you can see the manufacturer and model #, you should be able to find a replacement pretty easily by googling FORCECON DFS451205M10T.

[edit]
http://www.ebay.com/sch/i.html?_trk...nkw=FORCECON+DFS451205M10T&_sacat=0&_from=R40

Judging by the pictures of the part itself, it seems there are 3 screws holding the shroud/fan assembly in place. Should be easy to find out where you need to go & what you need to do from looking at the location of those mounting points.
 
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Yeah, you can see by the photo in post #9 that I managed to get it off. :p

I've ordered a replacement fan, so will install it when it arrives. I'll redo the thermal paste while I'm at it, since it can't hurt.
 
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DragonQ said:
Yeah, you can see by the photo in post #9 that I managed to get it off. :p

I've ordered a replacement fan, so will install it when it arrives. I'll redo the thermal paste while I'm at it, since it can't hurt.
Click to expand...

Sorry I missed that. Hope the replacement fan fixes your problems. If you don't know already, isopropyl alcohol and q-tips make it easy to clean up thermal paste like that.
 
FordFanboy said:
Sorry I missed that. Hope the replacement fan fixes your problems. If you don't know already, isopropyl alcohol and q-tips make it easy to clean up thermal paste like that.
Click to expand...
Not sure if I have any Q-tips but I have plenty of isopropyl alcohol left over from the last time I reseated a heatsink. In fact I might as well reseat my desktop's heatsink while I'm at it since that could use a de-dusting too!
 
Received the new (used) heatsink & fan today. I was going to get a new fan but when I searched for the fan's model number, all of the images that come up on shopping website don't match my heatsink's configuration.

Anyway, I de-dusted it then installed it with some new thermal compound (hadn't realised that I'd actually run out). Booted it and this time it didn't shut itself down which is good :D. After letting Dropbox index & sync, idle core temperature is now 25-35, instead of 60-70, and the fan can actually turn off when not needed. Mission completed, albeit with a broken Delete key. I think I bent the little clips so it doesn't sit properly any more. Not sure if anyone sells spare laptop keyboard clips. :(
 
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