More than likely NOT a simple adjustment. It's a very
common symptom caused by a gummed up clutch, (behind the
vertical playing turntable). You may have to find
experienced help, (service call), or another collector
willing to offer some help with a cleanup-relube.

You will find good information on youtube on how to
lube the mech, and also other Seeburg Jukeboxes displaying
this same exact symptom, with various collectors showing
where to lube the clutch assembly.