It appears to be line sync.
I've just had to swear at it... very loudly !
The lead from the tripler to the focus control broke down and made some unholy racket and very big sparks, so I thought 'I know, I'll just bung a new lead on it'.
A great idea until I broke the lead off the tripler trying to join a temporary new one on to it! (it's gone terribly brittle)
It's got to be said, it's been a year on and off, trying to find time to work on it and my patience is running very thin!
I photocopied the red book drawing at work and enlarged it, it's not too bad
The set is immaculate inside & out so I think it should be fixed & enjoyed.