Well, nice introduction and reply.
I was reluctant to be specific until I get a reply.
From experience and you have just confirmed it - some folks are like my father was - start from Adam and provide "advise" - such as "do you have another scope".
Then , and again nothing personal, some folks just do not read ( I mentioned I have a shop manual so why do I get advise to download it ?) and make wrong"assumptions".
BTW I have been using this particular scope professionally for few years - but that has nothing to do with the problem - except the box seen some countryside few times (!).
Perhaps that how the "screw got loose".
Anyway - the issue is as I suspected - the delay sweep setting is in unknown time setting since the funky coupling to the resistor ( R69 ) is missing the set screw.
Since I messed up with my original post - can moderators delete one of them?
Perhaps merge them together if it benefits the group.
PS I am on my way to the Ace hardware store - getting hex set screw 4x40 .125 - from shop manual.