Samsung S21 FE (G990) Repair: Wi-Fi and Bluetooth Not Working, Cannot Find Networks. Trace Break on the Second Layer

🛠 Difficulty: 🟢🟡🔴

⏰ Repair Time: ~2 hours

Today, a Samsung S21 FE came in again with the issue of Wi-Fi and Bluetooth not working.

Based on our experience, we initially expected that it would be a typical case of re-soldering the chip – which we did first.

Indeed, after replacing the chip, Wi-Fi and Bluetooth started working, but there was a catch: headphones played system sounds, but music or YouTube audio did not work.

We suspected a possible defect in the Wi-Fi module itself, so we replaced several modules for testing.

After these replacements, Bluetooth still didn’t work, and on top of that, Wi-Fi completely stopped working! 😂

A new hypothesis arose – most likely, there was a break in the traces leading to the chip on the second layer, which often happens on the boards of this particular phone model after physical impact.

For the repair, we remove/cut part of the metal frame at the corner and begin removing the first layer of the board.

We remove the fiberglass layer down to the second layer, where the necessary traces run.

At the spot indicated by the arrow, under the microscope, a break in four traces is visible.

Before restoring the traces, we install the Wi-Fi and Bluetooth module back onto the board ☝️

Using a thin copper wire, we carefully restore/connect the damaged traces.

The completed work looks like this in the image 🙂

We connect the PCB back into the smartphone housing for testing.

Wi-Fi, Bluetooth, and headphone music all started working immediately! 😀

We apply a UV mask over the repair area and secure the traces for reliability.

Then we reassemble the smartphone completely 👍