want to replace faulty hinges on my t420 -- your advice appreciated

[arooni]

got the cheapest new set of hinges on ebay which apparently didn't come with new screws. i'm wondering if you think it'd be enough to simply replace the hinges and re-use existing screws

i don't really want to start and find out i should have waited to get the screws too.

this is what i bought: https://www.ebay.com/itm/New-14-1-Hinge ... .Xfoo.TRS0

not sure if that's enough; this is also sold:

https://www.ebay.com/itm/NEW-Lenovo-Thi ... .Xfoo.TRS0

did i buy the wrong part?

thanks!

ps; anyone have a guide they'd recommend to complete the repair? thanks!

[shawross]

Unfortunately I think so. The T420s would be different to the T420 that you have. I don't have either but you have pulled the trigger too quickly I think.


You could check the HMM manual for your Thinkpad at the top of this page when you are logged in.

[turomini]

Reusing the screws is generally fine, I haven't replaced my screen, but its been off a few times. The man problem you might run into is stripping the heads if you don't have a proper small screwdriver. The screws were put in with some type of thread locker, and can be difficult to pull out the first time.

The T420 and T420s use different hinges.
T420 uses 04W1610, 04W1611, or 04W1612
T420s uses 04W3413, or 04W3414
T420s with multitouch uses 04W1707

Replacing the hinges is fairly straight forward, and the most complicated part might be dealing with the wires that run between the lcd panel and laptop base, which run through both hinges on a T420s. (one side is power, the other is data, but both sides also have antenna leads).

If its similar to other think pads I've worked on, you'll have to pull the keyboard and top bezel to remove the wires that run to the lcd panel. Then its just two screws on each side that hold the hinges to the base.
From there the most of the lcd panel has to come off, including the screen. This is a good time to update antenna leads (or replace in my case because one has been cut since i got the laptop, and I never noticed until after the warranty was out), camera, bezel or any other problem parts up there.

This will take some time if you've never done this before, so plan a good amount of time and don't rush. Stay organized and work in a large open area. There is a fair amount of little screws that you don't want to lose.

The Hardware Maintenance Manual has everything listed in there. The T420 HMM is located at the top of this site or directly: https://thinkpads.com/support/hmm/hmm_p ... 0i_hmm.pdf

[GrifterGuru]

Having literally had the screen off completely from my 4236-9N8 T420 today, I can state that it will take no more than 90 minutes if you take your time. I did it in 45 minutes and that including dismantling, swapping lids, swapping the LCD over to the new (old but better, not perfect though) lid and putting the thing back together.

Removing the hinge screws is two fold on a T420...

1) there are two screws under the palm rest bezel, to the right of the silver boss and just below the screen
2) There are two screws UNDERNEATH the base, at the back on the extreme outside edges. These screw into the base of the hinge tang (a solid idea in my book!).

Essentialy....

Changing a hinge REQUIRES:

Removal of the Charger (!!!!)
Removal of the battery (!!!!)
Removal of the palmrest bezel
Removing the keyboard
Removal of the Ram tray cover
Feeding wires from the RAM tray underneath, back through the mobo to the top inside of the base.
Careful lifting of some Ali-Foil tape
Removing the Screen Bezel
CAREFULLY moving the wifi and Camera/Thinklight wires to one side out of the hook/latch of the hinges.
Complete removal of the LCD unit for safe working and hinge replacement.

I would advise:

Completely remove the screen unit (entire laptop lid, if you like) to make life easy for yourself, rather than try to replace each hinge one at a time. You can then lay the screen flat on its back without worrying aout it moving around and damaging the other hinge.

I **MAY** be tempted to part with the excellent condition original hinges.. Maybe....


Also, whilst opened up, it is an excellent time to clean the cooling fan, the inside of the unit and maybe, if you want to, remove the heat pipes, clean the old thermal paste from the CPU * Heatsink, apply new and reassemble. It will certainly provide peace of mind knowin it has been done. No need to do it if you are not confident or comfortable enough to do it though.