Rapid ticking noise instead of sound from speaker

Hello everyone !

I successfully replaced the screen of my OnePlus 5T, however a problem remains : the speaker does not play any sound anymore.

Instead a rapid ticking noise can be slightly heard when playing a sound (music, call, video…) but also when starting some apps (WordReference for instance, which does not require any sound). The noise will last a little more if I pause the sound supposed ti be played.

I searched for a solution and found out that the speaker is dead (some talked about humidity) and bought a new one : replacing the speaker did not solve the problem.

What do you think could be responsible for this ? Are there any solutions ?

Many thanks !