The short answer is Do not spend $400 on a technician to repair a $100 fuser on a $500 copier.
Because these machines are legacy units (approaching 20-25 years old), Canon no longer produces brand-new OEM (Original Equipment Manufacturer) F151 300 fusers. Your market is now the secondary and remanufactured market. canon f151 300
According to documentation from A1 Used Computers and DriverGuide , the device features: : Up to 16 pages per minute (ppm). Print Resolution : 600 x 600 dpi. Duty Cycle : Up to 1,000 pages per month. The short answer is Do not spend $400