it's a phillips 8833 under the skin, i'm sure it will accept comp sync somewhere.
If you don't have sync, some early model 1084s are not pre-wired to accept sync from the SCART port. Wiring the sync to the composite input will not work either. The fix is to run a wire from SCART pin 20 to pin 2 of the 6-pin Analog RGB DIN input (labeled horizontal or composite sync on the pinout).