Laptop gpu overheating

Hi,

My laptop HP Pavillion DV5000 gpu Ati Radeon Xpress 200M Rs480 overheats and cause black sreen. I took it apart and saw a huge grey thermoplastic (?) heatsink installed over the chip and a thermal pad between. I think replacing thermal pad with a copper shim will cool down the laptop. However I noticed that the chip top surface is conductive and I am afraid to cause a destructive short. Is there a mica sheet (similiar type to that used to insolate transistor/heaysink) to be appplied in chip/heatsinc? Will you please help me with a hint to solve this problem.

Many thanks,

Peleida

I presume the notebook computer has been once working correctly. If so, you should be able to recover an operational state without hacking the hardware. The most likely reason for overheating is a cpu cooler, fan or dust filter covered with dust. Clean according to HP user/service instructions.

Do not substitute anything for the thermal pad. If the gpu or cpu are overheating, the cooling fan will speed up and be quite audible. Did you hear the fan racing?
If so, the heatsink might have failed. The copper tubing can contain a gas like helium for cooling and if a break develops it can escape. It requires a new heatsink ass'y.
However, if there was a thermal failure, when you power up again there is usually a bios message that it has occurred. As FvM said, cleaning can also remedy the problem.

Larry G

Hi,
Thank you for your replies for this problem. I should like to add that I cleaned the laptop properly e the only issue is the GPU overheathing (ATI Radeo XPress 200M RS480M). This part of circuitry has no fan but a big grey heatsinc which seems made of special metal as it is conductive and it is placed over the GPU with a thermal pad between the heatsink and the chip. According to may experience in power electronics this heatsinc is large enough to cool down the GPU but there may be a poor heat conductivity that I suspect caused by the thermal pad. What I intend to do is to replace thermal pad with a copper shim and the setbach is the top surface conductivity of the chip.
Narciso Peleida

Hi,

You say thermal pad, so probably not relevant, all the same - Have you looked to see (if it originally had any) that the thermal compound has dried out to the point of replacing with a fresh blob/squirt, or that by dismounting it the old stuff is no longer making contact between GPU and heat-sink and needs carefully removing in so far as is possible and replacing with a new blob/squirt of compound?

If it's a thermal pad, would a mica sheet (like for isolating transistors from heat-sinks, etc.) of some kind be a suitable replacement?

Equipment having heatsink designs based on passive heat conduction have their performance strongly enhanced by external forced ventilation. There are available on hot regions of the world cheap cooling stands designed with 2 fans which blows a continuous air flowing upwardly, and are able to reduce a bit the overall temperature. The only issue is when the outlet air of the Laptop is on its bottom surface, and the air flow is in the opposite direction of the stand coller, becoming this accessory useles.

retrogear said:

The copper tubing can contain a gas like helium for cooling and if a break develops it can escape.
Larry G

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Try with broken tube, you'll recognize almost no difference. I made it :-D The thermal conductivity of metal is enormous. In most cases the thermal grease dried out. Just replace it. And if you have a thermal pad, just put a little bit of thermal paste onto it. Don't use any metal shims.

If it has a thermal pad it's not likely to have thermal paste, you shouldn't use both together.

http://www.heatsink-guide.com/compound.htm

A good quality thermal pad can have reasonably good conductivity, paste is better.

The top of the GPU isn't likely to be conductive (as in electrical) it's a metal heat spreader to improve thermal conductivity most high power ICs are mounted with the die substrate insulated and mounted on the underside of that metal top. The die itself is usually flip chip (in more expensive package designs) with a substrate (pcb to route out to the solder balls). In lower cost applications they will have the wirebond die inside some sort of carrier in the pcb substrate and the die will be covered with a resin blob and the bottom of the die will have some thermal interface to the heat spreader. Hard to describe without pictures, but it's hard to find pictures of this online.

In short the top shouldn't short as it should be electrically isolated from the die. It's only there as a heat spreader and thermal interface to the heatsink. Make sure you clean both the heat sink and the GPU very very well, before putting on a new thermal pad or thermal paste (don't use too much!).

The advice not to use metal shims didn't refer to electrical conductivity but thermal contact quality. It's true that it's not the best to mix pad and paste but if he needs a fast solution, it does work. Or he removes completely all thermal pastes and pads, cleans carefully everything and apply a new pad or paste. It's his choice.

johnjoe said:

The advice not to use metal shims didn't refer to electrical conductivity but thermal contact quality. It's true that it's not the best to mix pad and paste but if he needs a fast solution, it does work. Or he removes completely all thermal pastes and pads, cleans carefully everything and apply a new pad or paste. It's his choice.

Click to expand...

I wasn't addressing your comment, but the following from their first post.

I think replacing thermal pad with a copper shim will cool down the laptop. However I noticed that the chip top surface is conductive and I am afraid to cause a destructive short.

Click to expand...

Hi,
Thank you for your help. Now I have a clear idea of what should be done to try solving this problem.

Peleieda