Motor control signals like the one shown here can be difficult to trigger on. The TekScope THS-720P addresses this problem with its "Motor" trigger type.

Pressing the "Trigger Menu" on the scope brings up the trigger menu.

By pressing the LEFT bezel button, you can set the trigger type to "Motor".

Clear the menu, then press the "Set Level to 50%" button. The scope will automatically set the trigger level to provide a stable trigger.

If necessary, set the trigger coupling to "HF Reject" for added stability.

Now that you have a stable trigger, you can zoom in on any part of the signal using the delay timebase.