Laptop repairs

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sydney
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Laptop repairs

Post by sydney » Wed Dec 07, 2016 8:39 pm

A bit of an unusual problem for stardot but you're a clever bunch so someone may be able to help me out here.
My cousin's son dropped their laptop on it's side and broke the psu connector internally and on the cable. She can't afford to get it repaired so I offered to bodge a repair for her by removing the broken connectors and soldering the psu directly to the wires internally. This was pretty easy to do but there seems to be another problem. After about ten minutes of use the laptop simply switches off and can't be turned back on, at least not for about an hour, even if it's been running from battery which makes me think my bodge isn't the issue. The fan seems to come on immediately when it's turned on and I'm thinking the problem is overheating as every link when googling points to that.
  • The fan and surrounding area were not particularly dusty
  • Is the power being removed immediately a sign of over heating?
  • If not what else could it be?
  • Could the fall have moved the heatsink somehow and how difficult is reseating it likely to be? I'm happy to have a go but if it's going to be a nightmare I'll probably not bother.
It's only about 5 pounds for a replacement internal cable and I could just add the correct jack to the psu cable and let her take it to a repair shop when she has some money so I don't want to make the problem worse than I possibly already have.

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danielj
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Re: Laptop repairs

Post by danielj » Wed Dec 07, 2016 8:49 pm

It does sound like it's overheating :( And yes, that could well cause it to turn itself off until it feels happier about life :?

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BigEd
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Re: Laptop repairs

Post by BigEd » Wed Dec 07, 2016 9:08 pm

Could be that a heatsink is no longer making good contact to a hot chip.

steve3000
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Re: Laptop repairs

Post by steve3000 » Wed Dec 07, 2016 9:39 pm

BigEd wrote:Could be that a heatsink is no longer making good contact to a hot chip.
Most likely.

I've taken apart a few laptops to repair bits and replace CPUs/etc. - google and youtube can be particularly useful in this regard. ;)

Often the heatsink is some form of heat pipe, secured in a number of locations by tiny screws - and running from the fan section across to the CPU/GPU - then forming a pressure contact to the CPU and GPU with either a film of heat transfer compound or a flexible pad. If the heatsink has deformed in any way, or one of the screws has dislodged, leading to loss of contact with either the CPU or GPU, then it is probably triggering a power cut-off mechanism after overheating.

Couple of things to try...

Are you able to run any software on the laptop before it dies? Something like Coretemp and gputemp (search google :)) will quickly show if either of these are registering increasingly high temperatures before shutdown.

And does the laptop still run from battery if you switch off at the mains plug? If it lasts significantly longer from battery, the overheating could well be the charging circuit.

Finally, if you close the laptop lid (so the screen shuts down) does it stay running for longer? Closing the lid will (usually) switch the GPU into low power mode as it's not needed, so it's a quick way to reduce temperature of the GPU.

Removing/replacing the heatsink/heatpipe is usually quite easy once you've disconnected and removed the keyboard/touchpad/etc. Definitely give this a try, and check for any signs of damage. Also, if the heatsink uses heat transfer pads to the CPU/GPU, they are simpler to ensure good contact when refitting (but they are less efficient), if it uses direct contact via heat transfer compound, it is more tricky to get a good connection - so take care - but when you do, it should be more efficient.

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sydney
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Re: Laptop repairs

Post by sydney » Wed Dec 07, 2016 10:11 pm

steve3000 wrote: And does the laptop still run from battery if you switch off at the mains plug? If it lasts significantly longer from battery, the overheating could well be the charging circuit.
By chance I turned it on again earlier with the battery removed and it worked for half an hour before I turned it off and came to bed. I'll let the kids play on it tomorrow for a bit of 'stress' testing! I'm sure she'd be fine using it without the battery in place.

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sydney
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Re: Laptop repairs

Post by sydney » Wed Mar 01, 2017 9:22 pm

Just to finish off this story:
The laptop continued to overheat so I undid my bodge so that my cousin could take it to a laptop repair shop. Whilst I had it apart i gave the whole machine a liberal spray with a can of compressed air and it seems to have just about done the trick. It has turned off a couple of times but this was apparently happening before it was dropped so hopefully it's back to being useful again.

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CMcDougall
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Re: Laptop repairs

Post by CMcDougall » Wed Mar 01, 2017 10:11 pm

^hope you enjoyed the screws under the keyboard .... :twisted: (who the feck thought of that! :roll: )
here is what I think of stupid slow as snails eMachines : :lol:
eMachine crap.jpg
slooooooow
Used it for parts for a older faster laptop :D

BUT, why on the underside of Laptops, makers make it easy to take out /put in : Ram, HDisc, Battery, WiFi and CMOS battery,
& forget totally about the worn out Fan's!! :roll: hacksaw and superglue fixed that though, but not ideal 8)
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CMcDougall
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Re: Laptop repairs

Post by CMcDougall » Sun Dec 31, 2017 2:27 pm

How to get to a fan not in 1+hrs, but 5mins :lol:
clean spindal with WD40, now nice & quiet, does not overheat & crash /hault!
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zeem
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Re: Laptop repairs

Post by zeem » Mon Jan 01, 2018 1:33 pm

Heatpipes can fail, causing exactly this problem. I've got an old laptop that overheats and powers itself off under heavy load, but has no dust in it, or visible damage, and my suspicion is the heatpipe. Try looking for a replacement heatsink assembly on eBay. The ones I was looking at were about £10 to £15.

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pau1ie
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Re: Laptop repairs

Post by pau1ie » Mon Jan 01, 2018 7:24 pm

My laptop is a Vaio and they are known for the thermal compound between the CPU and the heatsink failing. I took the heatsink, complete with heat pipes off, then added new compound and reattached it, and that made a massive difference. I cleared the dust away while I had it apart.
I'm working on http://bbcmicro.co.uk

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