Semco Motion Products / Larsen Mfg.                        +1 801-876-2111 

FG300-0 VSR Oscillating Control


Limit switches on the rotator’s main shaft control the amount of travel the TV display will go in each direction. When the limit switch is contacted it closes the normally open (NO) contact sending a +12V signal to the latching relay. This switches the controller’s 

FWD and REV wiring to change motor direction.


There are toggle switches for main power and for wireless on/off.

The Wireless switch has three positions, Wireless to allow the use of keyfob remote on/off. The middle position is Stop, the third position is Manual Run. Manual can be used to test run the rotator or use a hardwired on/off switch at the ground level.




Install as pictured above with switches at the top.


Disconnect the main power to the rotator

Remove the nuts holding the existing switches and speed dial to the rotator frame

Remove Motor wire connections


Limit Switches.

We provided a new cable for the microswitches but it may be easier to simply remove the cable from the existing board and install it in place of the new cable since the switch wires is secure and in place already. Simply trace the wire connected to the COM connection on the 

limit switches and connect this wire to +12V terminal with the red wire coming from the DC power supply When installing the new control board.


Disconnect main power cable connections feeding power to the rotator.

Disconnect motor wires from the control board wires.

Disconnect any cable clips holding the cables to the rotator frame. 

Remove the control panel by unscrewing four screws holding the control board in place and carefully remove the board.


Install the new board in place of the old board and connect cables and switches in place of those removed.


Connect the power cable on the board to the AC source 

Connect the motor cables using wire nuts. Polarity can be either way.

Connect the existing limit switch cable after removing the new cable or

Connect the three wires out to the microswitches coming out of the bottom of the board. Cut the cable to size so the wires.


When all connections are made make sure all cables are secure and that no wires are in the way of moving parts. Once that is done you can test run the rotator. But first note the position of travel and distance to the limit switch cams on the rotator shaft. It is important run the rotator in the proper direction so as not to over-run the limit switch and twist up the TV cables. 


Test run by switching the wireless toggle switch to stop, dial the speed control nob to about 25%, turn on the main power switch. Do not switch to manual yet.

Next, not the position of the TV Screen and where it stopped in its travel. If it is near the end of it’s travel, for example near the right of it’s travel, then on the main shaft the limit cam is near to hitting either the upper or lower limit switch. This should reverse direction. 

You can test this by flipping the toggle switch to Manual and watch the direction it is running. You can manually push in the toggle switch roller closest to the limit cam (be careful of moving parts) and see if it switches direction. If it does not change direction flip the toggle to Stop.

Reverse the two leads on the limit switch cable at the control board. The center and left terminals. Test again and make sure both limit Switches are working properly.