Speaker doesn't work

The usb c port of my bottom unit was broken so I swapped it for a new bottom unit. Immediately I had no speaker sound anymore (earphone works fine). So I bought a new speaker unit but it didn’t help. After putting the old units back in the speaker sound didn’t return.
I have latest update, tried starting fp3 in save mode did system check but to no prevail.
FP helpdesk wasn’t helpful. Any ideas here?
Greetings Edwin

Did you try to clean all contacts with alcohol, especially the upstream contacts?