《Resident Evil 9: Requiem》 Cinderbrook Apartments, Damaged Signal Receiver & Complete Detonator

Return to the location where you found the BSAA supply crate key, and this time enter through the main gate of Cinderbrook Apartments.

From here, climb the stairs to the apartment rooftop — you'll pass a crank slot along the way — then jump into the building's center to trigger a fight with an armored zombie. After eliminating all zombies, use the crank to open a door and escape, taking the rusty crank with you.

Once you have the rusty crank, return to the crank slot you passed earlier on the upper floor and use it to open the door. Things will immediately get tricky: there are zombies with mortars that will fire at Leon the entire time — hope your rifle aim is good enough. This is another linear area; you'll need to find cover and take out the mortar zombies one by one. The yellow crate next to the first mortar shell fired at you contains the next detonator part you need, though you'll have to take a detour to get it.

Eventually, you will find the Damaged Signal Receiver. Combine it with the broken detonator, then repair it using the repair kit you obtained earlier to create the complete detonator.

You can now go to the main gate to place the detonator at any time. However, once you trigger the explosion, you will leave this area of Raccoon City and cannot return. Be sure to complete all optional objectives first, such as finding all BSAA supply crates and collecting all Mr. Raccoon figurines, before proceeding.