Samsung Galaxy S9 Disassembly Teardown

The Samsung Galaxy S9 has to be opened from the back cover to the front, just like its predecessors. The back cover is glued and not screwed. The frame with the side buttons is stock of the display unit, which is replaced during a repair.

Since the display on the Samsung Galaxy S9 as well as the Samsung Galaxy S9+ reaches far to the edge at the top as well as the side, a glass breakage can happen quickly. An impact on the aluminum frame can also cause the glass to break since the force is transferred from the frame to the display.

As already mentioned, the back cover is only glued. It can be removed most quickly with heat. Care must be taken not to damage the induction coil when opening it.
Once the back cover has been lifted off, the 15 screws marked in red can be loosened. This will allow the top and bottom plastic covers to be removed.

Before proceeding with disassembly the SIM card holder should be removed. This prevents the removal of the mainboard.
Before the mainboard can be removed, all cables marked in yellow and the screws marked in red must first be loosened. After that, the careful loosening of the mainboard is possible.

After the mainboard is removed only the battery, front sensors and vibra unit need to be removed. All components can then be reinstalled in the reverse direction.

Opening the device is at your own risk. I assume no liability for any damage caused.
Nevertheless, I think this little overview can be useful for one or the other.