Before inserting your new module back in the housing, a blob of sauter that is used to protect the module during transport must be removed. Photo 1 shows this blob, in the yellow rectangle, marked red by the nice fellow who sold me the new laser so I would easily recognise it easily. Without removing this, the CD player will not function.

Heat the blob with a sautering iron and either flick it off or suck it up with a "sauter sucker" when it liquifies. After that the contact should look similar to photo 2.