Step 1: Unscrew the Middle Plate
You should first follow steps 1-5 of this Instructable to get the housing off of the Ember https://www.instructables.com/id/How-to-Remove-Embers-Linear-Drive/
You need to unscrew the 8 outside screws of the middle plate. There are 4 4x12mm and 4 4x30mm along the outside, remove them with a 2.5mm allan key. The screws to remove are circled in green remove the mirror image of these from the other side as well.
Step 2: Unplug the Motors and Sensors
You'll have to unplug the two motor plugs, the z-axis sensor cable, the jamming sensor, and the homing sensor. I've circled them all in a lovely shade of blue.
I find it easiest to remove the z-axis and homing sensor cables using a pair of pliers or tweezers with a hooked or bent nose. To remove the motor plugs I bring one hand in from the back and one from the front and squeeze my index fingers together over the latch and lift up.
Step 3: Lift the Central Assembly Off
Just grab the whole assembly by the linear drive and gently lift up, be sure to guide the z-axis motor cable out from beneath the projector. If lifting it up is at all difficult make sure you didn't forget to unplug a sensor because you can pull the wires right out of the sockets (or worse the socket off the board) and then you'll be sad.
Step 4: Remove the Projector Shroud
There are two plastic screws attaching the projector shroud use a No. 10 Torx to remove these. I find if you're careful you can also use an M3 allan key to remove these.
Step 5: Indent Screw Position and Remove Projector
The projector is placed so that it projects across the whole build area if it is placed incorrectly part of the projection will be cut off. To make sure that you can place it back where it was I first tighten the screws holding it down to make a visible dent so that I can line everything back up when I put it in. There are six screws holding it in place all of them are M3x12mm circled in green, you can remove these with an M2 allan key. You'll have to clip the zip tie holding the plug in place and unplug the HDMI cable as well as the I2C cable all circled in blue (the I2C isn't pictured plugged in). Then you can lift the whole projector, sleigh and all, out of Ember.
There's a picture above of the dent left after tightening the screw and then removing it. You can make sure that you put it back in the right spot before fully assembling it by putting the central assembly in place and inserting a resin tray on the platform and rotate it directly over the window. Then boot Ember, ssh in, and type the command echo test > /tmp/CommandPipe and make sure the whole image is displayed in the bottom of the resin tray. You don't have to plug in any of the motors or sensors or anything, but you might want to put two screws in the middle plate just to make sure it's in the right spot.
IMPORTANT NOTE FOR REASSMBLY: The green I2C cable is asymmetric, it will either have a side that has a sharpie mark or the ends will be labelled with J2 on one side and J1 on the other. The side that says J2 or the side with a sharpie mark must be plugged into the projector.