HP LaserJet Pro Color MFP M476dw - Page 9

Fax by using Voice over IP services ................................................................................................... 34
The fax subsystem ............................................................................................................................ 35
Fax card in the fax subsystem .......................................................................................................... 35
Safety isolation ............................................................................................................... 35
Safety-protection circuitry ............................................................................................. 35
Data path ......................................................................................................................... 35
Hook state ....................................................................................................................... 36
Downstream current detection ...................................................................................... 36
Hook switch control ........................................................................................................ 36
Ring detect ...................................................................................................................... 36
Line current control ........................................................................................................ 36
Billing- (metering-) tone filters ...................................................................................... 37
Fax page storage in flash memory ................................................................................................... 37
Stored fax pages ............................................................................................................. 37
Advantages of flash memory storage ............................................................................ 37
USB flash drive ..................................................................................................................................................... 38
2 Solve problems ........................................................................................................................................... 39
Solve problems checklist ..................................................................................................................................... 40
Menu structure .................................................................................................................................................... 42
Configuration report ............................................................................................................................................ 43
Troubleshooting process .................................................................................................................................... 44
Determine the problem source ......................................................................................................... 44
Power subsystem .............................................................................................................................. 45
Power-on checks ............................................................................................................ 45
Control-panel checks ........................................................................................................................ 45
Tools for troubleshooting ................................................................................................................................... 46
Individual component diagnostics .................................................................................................... 46
Tools for troubleshooting: LED diagnostics ................................................................... 46
Network LEDs ............................................................................................... 46
Control panel LEDs ....................................................................................... 46
Tools for troubleshooting: Engine diagnostics .............................................................. 47
Engine-test button ....................................................................................... 47
Drum rotational check ................................................................................. 47
Half self-test functional check ..................................................................... 48
Diagrams ........................................................................................................................................... 49
Diagrams: Formatter connections .................................................................................. 49
Diagrams: Location of major components ..................................................................... 50
Major components ........................................................................................ 50
Motors and fans ............................................................................................ 52
Rollers ........................................................................................................... 53
ENWW vii