City Theatrical Follow Spot Yoke
4
Installing the Source Four into the Follow Spot Yoke
Note the two Tee Blocks that slide into the Tee Slot Extrusion. Using a 3/16” Allen key,
slightly loosen the two 3/8” x ½” socket head shoulder screws to free the Tee Blocks.
Carefully insert the Tee Slot Extrusions onto the Tee Blocks. Tighten the tilt handwheel.
Temporarily tighten the shoulder screws. Install four 4-
40 x ¼” pan head machine screws,
one in each end of each Tee Slot Extrusion. These screws serve as safety devices to prevent
the Tee Blocks from accidentally slipping out of the Tee Slot Extrusion track.
Install the Lens Tube into the Source Four
Install the Lens Tube into the Source Four and install the two #10-32 screws (one plastic
thumbscrew and one Philips machine screw) that hold the Lens Tube to the lighting fixture.
Plug in the lighting fixture into a switch or dimmer and dress the cable to insure that it does not
restrict the yoke’s movement or its balance. Turn on the lighting fixture and adjust the
sharpness of the beam to the degree that you think is appropriate.
Balance the Lighting Fixture in the Yoke
The lighting fixture can be adjusted forward or backward in the Tee Slot Extrusion to establish
a perfect balance point. To test the balance, carefully loosen the tilt locking knob and feel if
the fixture is front heavy or back heavy. To adjust the balance, loosen the two shoulder
screws and evenly push the fixture forward or backward in the Tee Slot Extrusion until it
balances exactly. Lock the shoulder screws again. Test and repeat if necessary.
Shoulder screw
Tee Slot
Extrusion
Tee Block
Tilt handwheel
Adjust balance as needed
For 5º Source Four
Tee Slot Extrusions overhang toward front of
lighting fixture. Shutters may or may not be
removed.
For 19º-50º or 10º Source Four
Tee Slot Extrusions overhang toward rear of
lighting fixture. Shutters must be removed.
