HP LASERJET ENTERPRISE M855 - Page 64

Figure 1-7 Fuser system block diagram
Fuser PCA
FSR_SL_TH
TH4
DC controller
Low-voltage
power supply
TH1
TH2
TH3
Heater
Pressure roller
Fuser
New part detection fuse
100V-200V
discrepancy
circuit
+3.3V
Triac 2
Triac 1
Relay 1
Relay 2
Triac 2
drive circuit
Triac 1
drive circuit
Relay 1
drive
circuit
Relay 2
drive
circuit
Safety
circuit 3
Safety
circuit 1
Safety
circuit 2
Fuser
current
detection
circuit
Inlet
current
detection
circuit
AC input
Noise
filter
Zerocross
circuit
FSR_D2
FSR_F_TH
FSR_R_TH
FSR_SS_TH
FSR_D1
/FSR_RLD
+24V
+3.3V
GND
FSR_CURRMS
/ZEROX
INL_CURRMS
FSR_NEW
FSR_100 FSR_200
TP101
H1
H2
H3
22 Chapter 1 Theory of operation ENWW