Brother International HL 1850 Service Manual - Page 198

HL-1850/1870N SERVICE MANUAL M-5 Insufficient output from high-voltage power supply unit Possible cause High-voltage contact High-voltage power supply PCB Step 1 2 Check Do any of the terminals on the high-voltage contacts have dirt or contact burns? Check the connections of the connector between the highvoltage power supply and the engine PCB are secured correctly. Result Remedy Yes Clean the terminals. Yes Replace the high-voltage power supply PCB No Reconnect the connector between the high-voltage power supply and the engine PCB. M-6 Fixing heater temperature failure Possible cause Poor thermistor harness contact Blown thermal fuse Thermistor failure Halogen heater lamp failure Step 1 2 3 4 Check Is the contact of connector P6 on the engine PCB good? Remove the fixing unit and measure the resistance of the thermal fuse. Is it open circuit? Is the thermistor installed properly? Remove the fixing unit and measure the resistance of the halogen heater lamp. Is it open circuit? Result No Yes Yes No Yes Remedy Reconnect the connector. Replace the fixing unit. Replace the fixing unit. Reinstall the thermistor properly. Replace the halogen heater lamp. M-7 BD failure Possible cause Harness connection failure Step 1 Check Is connector P10 on the main PCB secured correctly? Result No Remedy Reconnect the connector securely. Yes Replace the laser unit. 6-31