The clockmaker's test

An original fiction passage set in the nineteenth century.

Mr Ainsley arrived before the town-hall doors were opened. The clock had stopped during the night, leaving both hands fixed at twenty minutes past three. He removed the wooden casing and turned the mechanism carefully. A cracked cog caught against the winding drum, while a loose chain sagged beneath it. Mr Ainsley closed his tool box. He would give the caretaker his report before beginning the repair.

Give two faults Mr Ainsley finds in the clock mechanism.