I stumpled upon schematics and an assembly drawing of my laptop (Thinkpad P14s, Gen 1) on a computer repair forum. While studying the schematics is interesting in itself, it also allows me to perform board-level repair, as I can see what each component does, which voltages to expect, and what the pinouts and part numbers are.

USB-C Replacement

One USB-C port has been broken for a while, so I challenged myself to replace it. I couldn’t find the exact replacement connector with the same part number at Mouser or Digikey. However, there are many sellers on Ebay who offer parts for specific laptop models, so I ordered there. I disassembled the laptop and removed the main board, and used Kapton tape and aluminum foil to mask off the area of interest in order to protect the other components. I desoldered the connector using a heat gun.

After cleaning the PCB with isopropyl alcohol and applying a little amount of solder paste and a healthy amount of flux, I reheated the PCB again to solder the new connector. After checking for shorts and putting everything back together, the USB port works again!

Fan Replacement

Suddenly, my laptop made weird clicking noises when I booted it up and the fan was not spinning anymore. The fan probably broke because I was moving the laptop too fast once when the fan was spinning, resulting in some of the blades hitting the fan casing and breaking off. I could temporarily “fix” it by removing the broken blades, but of course this resulted in reducing cooling performance as well as more vibrations, as the rotor was now unbalanced.

I ordered a new fan on Ebay and replaced the old one. The replacement was straightforward and did not require soldering. It also gave me the chance to replace the thermal paste of the CPU and GPU.

Keyboard Replacement

At one point my Enter key started to feel a bit wonky, and after clicking it back a few times the plastic hinge finally broke off, leaving me with a keyboard without an Enter key. So I searched for individual keys and whole keyboards. Replacing the whole keyboard just made more sense money-wise.

The keyboard can actually be disassembled without removing the back cover. Instead, the two touch pad buttons can be removed, which reveals two screws. Undoing them allows the whole keyboard assembly to slide down, which unhinges it allows it to be lifted out of the frame. Clever design choice!

I was a bit careless when undoing one of the two flat-flex connectors on the motherboard, which caused the hinge of the connector to break. This flat-flex cable seems to power the TrackPoint and the keyboard backlight. There are also signals for the physical trackpad keys, but those are actually coming from the other, bigger connector, but are looped backed into the TrackPoint assembly (which contains some active logic) via this smaller cable, presumably to filter out disturbances from the key presses.

Instead of finding a replacement FFC connector, I decided to completely remove the broken connector and instead solder the cable directly to the board. I used individual pieces of magnet wire to connect the cable to the board, and used Kaptop tape to hold everything in place.

I am glad I replaced the whole keyboard instead of just the broken key, although it was a bit more work than expected. The new shiny keyboard has better haptic feedback than the old one, which probably started to wear out a bit.