T420s disassembly and clean

[zern]

I just successfully disassembled and cleaned my 3 year old T420s. Here are some thoughts and observations that may be useful to someone.

MyT420s has been running burning hot and sluggish lately. It is in daily heavy use. Idle temps around 80C, quickly spiking up to 98C without much loading. I'm guessing the sluggishness comes from the cpu throttling back to avoid getting to the 100C shutdown threshold.

The hardware maintenance manual HMM was indispensable. Just about every part needed to be removed in order to get at both sides of the fan. The whole process took about 1.5 hours. It is important to set aside a quiet time to do this.

Before unplugging the antenna cables from the wifi and wlan daughter cards, take a photo to remember which coloured cable went into which connector. There are 5 coloured cables in mine, with identical connectors. The HMM does not show the colours.

There are a lot of screws to remove. The screws are not identical. I laid out strips of blutack that corresponded to the positions of the screw holes on the case, and methodically stuck each removed screw onto the blutack. This allowed me to see where each screw went, and stopped them rolling off my desk.

Make sure you have enough desk space to lay out each piece as they are removed.

All I needed to remove the screws was a small jeweller's Philips screwdriver. I also found a flat blade screwdriver useful to peel back the sticky tapes, and to work cables out off and back into the cable management tabs. Be careful about accidentally nicking/damaging the insulation of the cables with the screwdriver. I did that and had to put tape around the teeny tiny and fiddly damaged area.

The parts can feel fragile when disassembled. But they are not made of eggshells either. Gentle jiggling was needed to remove and refit the piece containing the speakers and touchpad assembly. Sometimes when a piece refuses to budge it can be due to an undetached cable. Rough sudden yanking is not recommended! A part that doesn't sit flush will need to be gently rocked and jiggled into place. The tolerances are quite tight so the pieces should fit snugly before screws are attached. Don't force anything to fit.

I did not detach the fan assembly from the motherboard. I did check that the heat pipes were firmly attached to the cpu.

Cleaning was done with a can of compressed air, and a slightly damp cloth. When blowing dust off the fan and its surrounds I made sure to hold the blades with a finger to stop the fan spinning. The was quite a lot of dust between the curved blades.

I also used a household vacuum cleaner (with the dusting brush attachment) to clean the less delicate parts like the chassis and keyboard.

After reassembly, I ran the fan on turbo speed for about 15 minutes to clear out any stuck pieces of dust from the fan.

Idle temps are now 45-55C. I call that an improvement! And the machine feels zippier too.

[RealBlackStuff]

I would still advise you to re-do part of it again.
Remove the heatsink from the CPU, clean of the old rubbish with 91% Isopropyl Alcohol, then apply fresh AS5, as described here:
http://www.arcticsilver.com/pdf/appmeth ... d_v1.1.pdf
The gunk that's in there now is already at least 3 years old and more than likely fully dried out!

[rkawakami]

Nice descriptions and tips, especially using blutack. I use a plastic sectional box with small slips of paper describing which FRU or part the screw(s) came from in each compartment. If I left screws out on the desk, sticking up from some tacky stuff, my cat would come over to investigate and as she has pica, would probably ingest a few of them .

I did not detach the fan assembly from the motherboard. I did check that the heat pipes were firmly attached to the cpu.

Given that you did almost an entire teardown to the motherboard, it would not have taken much more time and effort to remove the heatsink/fan (HSF) assembly and replenish the thermal grease. That one item is fairly important in maintaining the cooling efficiency of the HSF. It degrades over time and at three years old, it's probably about middle-aged.

[zern]

I had thought about the thermal grease but didn't have any replacement at hand. I did check that the screws holding the heat pipes in place are still snug.

thermal grease will be something to do next year...

Yes if you have a cat, make sure it is well fed and sleeping before beginning this task!

[anthony]

Thanks for the post. Great overview...