Chances are real good that you need a new clock motor
The white plastic cog tends to split. The motor will continue running, but it will not keep time and it will not advance on it's own.
By-pass the system.
Use a Sharpie to mark the cog on the motor and the cog just above and meshed with it.
Check it after 10 minutes. If it has not moved you need to replace the old one, set the correct time and put the system back in service.
If all is well the system will finish regenerating and you will be back in business.