specto projector jittering

[gahoona]

Hello. I have a specto 16mm projector, It jitters quite alot, What is generally the cause of the jumpy picture.
thanks

[gahoona]

Test film had torn sprockets.
Specto is new to me from ebay, deceased estate.
I used a different roll and it worked beautifully. An amazing and easy to use projector .
Thanks granfer for the suggestion in 2008 in a different thread.

[granfer]

My pleasure!