I have the Pfaff Tiptronic 2040 and have changed the light bulb a couple times---there is a white plastic thing with slots in the round end which fits up over the bulb. You push it up as far as it will go and then turn it half a rotation counterclock-wise and pull it out. insert the new bulb in the slots and push it upward into the machine as far as it will go--then turn it half a turn clock-wise and pull the holder off the bulb. Should have your machine laying on its side when trying to do the changing so you can see what you are trying to do. Hope this helps with your machine and if I can help any more just pm me. I've never been able to open my machine case, either.