The gripper mech likely needs lubrication. Hot air from a hair blower can often help loosen up the old grease if it is locked up.
Otherwise would I just plug it in? Oh, I dunno. I probably would. But I've tinkered with these things for 35 years and know how to spot trouble pretty well.
If you are completely clueless about how to service these machines you would be far better off finding someone who really understands them.
And, just because someone claims to know how to fix TV's or computers or whatnot doesn't mean they know the first thing about jukeboxes.
So, choose an experienced repair person wisely. If that is impossible where you live order a manual and have your electronics repair person *thoroughly* read and understand it before they even touch your machine.
I cannot tell you how many hack "repair" jobs I have had to go back and fix due to someone who "thinks" they can repair one of these beasts and ends up just making a huge mess.
Just my .02. Good luck! --Ed