A known problem of aging HDI Advance systems is a problem with the projector overheating.  This causes the unit to shut off to avoid permanent damage.  This is usually caused by a failure of the cooling fans.  Sometimes dust or moisture can get inside of the scanner.  This can get stuck on the fan blade or fan blade shaft preventing them from operating correctly.  To clean these areas users can blow air into the vents.  A computer keyboard cleaner is very good at getting anything lodged in the deeper components loose.  The one pictured below can be found at most office supply stores.  Only use the spray if the scanner has been off for several hours.  The air that comes out can be very cold and can shock the electronics if they are warm from being active.