As helpful and informative as this DIY is, there is one bit of incomplete/incorrect information that if followed exactly as it reads, is possible to destroy the logic board. I believe I did just that.
In step 2, the DIY reads:
No, it does NOT!
Next we need to remove the motherboard, firstly disconnecting all the connectors around the edges of the motherboard. Most will just pull out, but the the ones with flat ribbon cable have a special way of disconnecting. Basically The black piece needs to be carefully levered away from white part as you can see below. The same goes for the ones connected to the optical block.
That is correct for the one small ribbon cable on the left side of the projector that connects to the onboard control panel. IT IS NOT CORRECT FOR THE THREE RIBBON CABLES WHICH CONNECT THE LCD PANELS TO THE LOGIC BOARD!!!
On those three connectors, the ribbon plugs into the black housing, and a small beige lever rotates up away from the board to release the cable. I would have guessed that if the DIY hadn't led me to second-guess myself and believe otherwise. I popped all three of those bars off the connector before I realized what had gone wrong. Unfortunately, they're impossible to reinstall without ruining either the bar or the connector. One of my small bars is broken in half because I was trying flex it to get it back into the housing, and one flange that the bar inserts into is broken on two other connectors.
I'll talk to a repair tech tomorrow, but I assume the projector is essentially destroyed at this point.
These are tiny pieces. Knowing what I know now, I consider that the only very risky part of the repair, and it absolutely should have been called out as a separate caution item.
Just wanted to warn anybody who pursues this DIY to be very careful with those ribbon connectors. They're both a latch, and they compress the spring pins onto the ribbon cable.
If anybody needs the Epson 1452666 Motor Assembly, I have a spare, and will likely have any other spare parts other than a logic board.