Just went through removal and errors on mine. It's a pain. The spider is held on by a zip tie if you want to remove it. The pointer is held with a small set screw on the back side of the translite. You have to take one of the adjacent light boards off to get an allen wrench from the side to remove. Then pull off the pointer from the front. Remove the four screws from the back and the opto board pops off.
My issue turned out to be the connector at the MPU. There's a plug with a single wire in it below the normal switch matrix plug that has this opto on it. Mine wasn't seated well.
To test the opto before yanking it, go into test mode and spider test. It will rotate the spider and show you encoder counts of the motor and the state of the opto. If the encoder counts up then your motor and connectors are good. If you see it count up and then don't see the opto change state, it's the opto or connector. Play around with both ends of the connector (spider board and MPU) before yanking it.