On the plastic sides of the case, near the back, there are 2 holes - one on each side. Inside these holes are recessed plastic tabs. You should be able to look in the holes and see part of the tab.
They don't take much force, but if you insert a straightened paperclip or coat hanger, just enough to push the tabs a couple of millimeters, you can then slide the top half of the case forward and off.
Answers & Comments
On the plastic sides of the case, near the back, there are 2 holes - one on each side. Inside these holes are recessed plastic tabs. You should be able to look in the holes and see part of the tab.
They don't take much force, but if you insert a straightened paperclip or coat hanger, just enough to push the tabs a couple of millimeters, you can then slide the top half of the case forward and off.
kind of difficult with one person but certainly doable. On my unit the holes are covered up by black NDAS stickers.
Thanks Kerry!