Circuitmess MAKERbuino Build Manual page 21

Step 9 – Nokia 5110 LCD screen
Important: Firstly, check the photo next to this text
and determine the version of the screen you have.
If you've got the new screen, just proceed.
If you've got the old screen, you will have to solder the tiny female connector first and then plug the Nokia screen into the connector.
If you've got a new screen, you will just have to solder it
directly to the PCB.
You'll need M2 screws, nuts, and spacers for mounting
your screen.
Important: check whether the soldering joints on your
microcomputer's socket are soldered nice and clean and
that they are all shaped like a "volcano".
You have to make sure connections on the
microcontroller are good because you won't be able to fix
them after you solder the screen (the screen overlaps the
socket's soldering joints).