Samsung Galaxy S21 5G (G991B) with no sound and no SIM card detection! (SOLUTION)

☝️ To see how to disassemble this smartphone, check out the detailed guide here: [how to disassemble Samsung Galaxy S21 5G]

In recent years, one of the most common issues in Samsung smartphones has been the **very weak cable connectors**, which can get damaged even with minor mechanical stress. 😒

In this case, it’s almost certainly the same problem.

1️⃣ Carefully remove the back cover after heating the back cover to 50°C (122°F), then remove the wireless charging module.

2️⃣ Inspect the connector for the sub-board cable — only to find that the lower part is completely missing! 😳

3️⃣ From here, it’s business as usual.

4️⃣ Desolder the damaged connector. 

5️⃣ Clean the contact pads, apply flux, and prepare a new connector.  

6️⃣ Install the new connector. Temporarily reconnect the board to the device and test it.  

7️⃣ Everything works perfectly — both SIM cards are active, and the sound is back! 😃