Component Function TH2 Sub thermistor 1 Detects the temperature at ends of the fuser heater (contact type) TH3 Sub thermistor 2 TH4 Sub thermistor 3 Figure 1-9 Fuser control system AC input 16 Chapter 1 Theory of operation ENWW Low-voltage power supply DC controller Zerocross detection /ZEROX circuit High-voltage power supply RL1001 RLD Relay drive circuit RL1002 FSRD1 Fuser heater FSRD2 control circuit Current Fuser heater safety circuit detection FSRCUR circuit Fuser control circuit MFSRTH S1FSRTH S2FSRTH S3FSRTH Fuser Fuser film assembly TH2 TH1 TH3 TH4 TP1 H1/H2 Pressure roller Fuser film assembly TH2 TH1 TH3 TH4 TP1 H1/H2 Pressure roller Zerocross detection circuit RL1001 RL1001 FSRD1 FSRD2