HP M425

Drum cleaning stage ................................................................................................ 26
Step 7: Drum cleaning .............................................................................. 26
Pickup and feed system ........................................................................................................... 27
Jam detection ......................................................................................................... 30
Paper feeder (optional Tray 3) ................................................................................................. 32
Paper feeder operation ............................................................................................ 34
Jam detection ......................................................................................................... 35
Scanner system ...................................................................................................................... 37
Scanner power-on sequence of events ....................................................................... 37
Copy or scan sequence of events .............................................................................. 38
Fax functions and operation .................................................................................................... 39
Computer and network security features ..................................................................... 39
PSTN operation ...................................................................................................... 39
Receive faxes when you hear fax tones ...................................................................... 39
Distinctive ring function ............................................................................................ 40
Use fax with voice over IP services ............................................................................ 40
The fax subsystem ................................................................................................... 41
Fax card in the fax subsystem ................................................................................... 41
Safety isolation ........................................................................................ 41
Safety-protection circuitry .......................................................................... 41
Data path ................................................................................................ 42
Hook state ............................................................................................... 42
Downstream device detection .................................................................... 43
Hook switch control .................................................................................. 43
Ring detect .............................................................................................. 43
Line current control ................................................................................... 43
Billing- (metering-) tone filters ..................................................................... 43
Fax page storage in flash memory ............................................................................ 43
Stored fax pages ...................................................................................... 44
Advantages of flash memory storage .......................................................... 44
USB flash drive ...................................................................................................................... 45
2 Solve problems ............................................................................................................... 47
Solve problems checklist ......................................................................................................... 48
Menu map ............................................................................................................................ 50
Troubleshooting process .......................................................................................................... 51
Pre-troubleshooting checklist ..................................................................................... 51
Determine the problem source ................................................................................... 53
Power subsystem ..................................................................................................... 54
Power-on checks ...................................................................................... 54
Control-panel checks ............................................................................................... 54
vi ENWW