Reset PIN code Samsung DH48D

I have a customer that have forgotten the pin-code for their Samsung signage screen (DH48D).

Thought that would be easy to solve, but so far i haven't succeeded.

Thru Google searches I have found various combinations of key-pressing on the remote that should do it, but most are for Smart TVs, so far nothing is working.

I called Samsung support and they said that I need to have a service remote for it to work, so I ordered one copy of a Samsung service remote, that isen't working either (could be an incompatible copy).

Does anyone know the correct procedure for this?