Taking this off is way difficult. The black disk connects to the RA clutch lever. When you torque the RA clutch lever this allows the black disk to engage the motor and turn the entire RA base assembly. Removal is semi difficult and and prone to shearing the Declination wires. Reassembly is very difficult with 2-3 hours of trial and error.
One has to be extremely careful to not twist (sever) the wire bundle entering the the middle of the shaft. The shaft with a few threads showing in the center of the black disk connects to the RA torque lever. ( other side of the plastic base). If the silver threads ( middle of the black disk) are rotating you are about to shear the dec control cables!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Here is a helpful link from the great Weasner site with pictures: http://www.weasner.c.../inside125.html
Before disassembly occurs:
1. Note how many aluminum threads are showing from the middle of the black disk. Usually 1 -3 are showing. When reassembling this is important as it allows the RA lever to clamp down and engage the entire aluminum assembly. Otherwise it is a painful trial and error process.
2. Lock and unlock the silver RA clutch lever and note that the screw threads in the middle of the black disk rotates about 1/16 turn. Remove the sliver RA locking lever on the other side of the base. Use an appropriate hex wrench.
3. Underneath the silver RA lever is a hex head nut. The nut/bolt is hollow, the four wires in the middle of the black disk go through the bolt and exit about 1/2 inch from the top of the bolt. These wires connect to the declination motor in one arm of the mount.
4. Remove the blue electrical connector from the PC board. Mark the position of the connectors. In your case, yellow goes toward the edge of the PC board. Red towards the middle.
5 Use a 13mm socket wrench and unscrew the hex head nut, no more than one half turn. Remember you can shear off the 4 cables if you turn any further. As you turn the nut ( no more than one half turn) you will hopefully note the black aluminum disk will loosen up enough to hand loosen the disk. Push down on the hex head nut with one hand and try and unscrew the black disk with your other hand. You are trying to move the black disk away from the worm gear assembly.
Never turn the silver bolt!! Only unscrew the black disk..
6. Unscrew the black disk slowly. Only the black disk should rotate not the silver threads. If the silver threads move this will shear the wire assembly.
7. If the black disk refuses to hand loosen you will have to take apart the base.
7. Try your luck. I can send further instructions for the base disassembly. This is a 2-3 hour procedure. If you shear the Dec wires then you can fix them but will need replacement wires, heat shield, and a punch down tool.