Delayed response here, got caught in the earlier posting problems.
The jury runs the show. It’s up to them to come to the judge and say “we’ll can’t agree”. Until then, they set their own schedule (within reason), and can talk until Sanford freezes over.
If they do return, usually the judge will read them an instruction that says, “try harder” and send them out again. If they come back and say, “No, see... we really can’t agree”, the judge will excuse them and declare a mistrial.
Getting ready for the dance . . .