Table Of Contents - HP LASERJET ENTERPRISE M725dn Troubleshooting Manual

Table of contents

1 Theory of operation .......................................................................................................... 1
Basic operation ........................................................................................................................ 2
Function structure ...................................................................................................... 2
Operation sequence .................................................................................................. 2
Engine control system ............................................................................................................... 4
DC controller PCA ..................................................................................................... 5
Low-voltage power-supply PCA ................................................................................. 11
High-voltage power-supply PCA ................................................................................ 14
Fuser control ........................................................................................................... 16
Laser scanner system .............................................................................................................. 21
Laser scanner failure detection .................................................................................. 22
Laser scanner safety function .................................................................................... 22
Image-formation system ........................................................................................................... 23
Image-formation process .......................................................................................... 25
ENWW
Motor control ............................................................................................. 7
Motor locations ........................................................................... 7
Failure detection ......................................................................... 8
Fan control ................................................................................................ 9
Fan locations .............................................................................. 9
Failure detection ....................................................................... 10
Over-current/over-voltage/overload protection ............................................ 12
Safety interruption .................................................................................... 12
Power supply voltage detection .................................................................. 13
Sleep mode ............................................................................................. 13
Power supply illumination control ............................................................... 13
Fuser temperature control .......................................................................... 18
Fuser heater protective function .................................................................. 18
Fuser failure detection ............................................................................... 19
Pressure roller cleaning ............................................................................. 20
Latent-image formation block ..................................................................... 25
Step 1: Primary charging ........................................................... 25
Step 2: Laser-beam exposure ...................................................... 26
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