HP Color LaserJet CM4730 MFP

Performing preventive maintenance .................................................................................................. 128
ADF maintenance kit ........................................................................................................ 128
Calibrate the scanner ........................................................................................................................ 129
Set the real-time clock ....................................................................................................................... 130
Set the date format ........................................................................................................... 130
Set the date ....................................................................................................................... 130
Set the time format ............................................................................................................ 130
Set the time ....................................................................................................................... 130
4 Theory of operation
Basic operation .................................................................................................................................. 134
Operation sequence ......................................................................................................... 135
Operation sequence (scanner) ......................................................................................... 135
Power on sequence .......................................................................................................... 136
Formatter system ............................................................................................................................... 138
Sleep mode ....................................................................................................................... 138
Image Resolution Enhancement technology (REt) .......................................................... 139
Input/Output ...................................................................................................................... 139
Parallel interface .............................................................................................. 139
USB 2.0 connector ........................................................................................... 139
ACC accessory port ......................................................................................... 139
Flash ................................................................................................................. 140
Hard disk .......................................................................................................... 140
CPU .................................................................................................................. 140
FIH (foreign interface harness) ........................................................................ 140
MFP memory .................................................................................................................... 140
Read-only memory ........................................................................................... 140
Random-access memory ................................................................................. 140
DIMM slots ........................................................................................................................ 140
Flash memory .................................................................................................. 140
Nonvolatile memory ......................................................................................... 141
PJL overview ..................................................................................................................... 141
PML ................................................................................................................................... 141
Control panel ..................................................................................................................... 141
Scanner interface .............................................................................................................. 141
Engine control system ....................................................................................................................... 142
DC controller PCB ............................................................................................................. 142
Block operation ................................................................................................ 144
Motors, fans, and environment sensor ............................................................................. 144
Failure detection ............................................................................................................... 147
Drum motor failure detection ............................................................................ 147
Fuser motor failure detection ........................................................................... 147
ETB motor failure detection ............................................................................. 147
Rear exhaust fan failure detection ................................................................... 147
Cartridge fan failure detection .......................................................................... 147
Delivery fan failure detection ............................................................................ 147
Power supply fan failure detection ................................................................... 148
Scanner fan failure detection ........................................................................... 148
ADF fan failure detection ................................................................................. 148
Control fans #1 and #2 failure detection .......................................................... 148
ENWW vii