CHAPTER 6 TROUBLESHOOTING
6-32
M-8
Scanner failure
Possible cause
Step
Check
Result
Remedy
Harness
connection
failure
1
Is the connection of the
scanner motor connector P12
on the engine PCB secure?
No
Reconnect the connector
securely.
Power supply
input
2
Is the voltage between pins 1
(+24V DC) and 2 (GND) of
connector P12 on the engine
PCB 24V DC?
No
Check if +24V DC is supplied
between pins 2 (+24V DC)
and 3 (+24V RET) of
connector P5 on the engine
PCB. If not, check the power
supply output on the low-
voltage power supply PCB.
Yes
Replace the laser unit.
M-9
Fuser failure
Possible cause
Step
Check
Result
Remedy
Poor thermistor
harness contact
1
Is the contact of connector P6
on the engine PCB good?
No
Reconnect the connector.
Blown thermal
fuse
2
Remove the fixing unit and
measure the resistance
between the input connectors.
Is it open circuit?
Yes
Replace the fixing unit.
Thermistor
failure
3
Is the thermistor installed
properly?
Yes
Replace the fixing unit.
No
Reinstall the thermistor
properly.
Halogen heater
lamp failure
4
Remove the fixing unit and
measure the resistance of the
halogen heater lamp. Is it
open circuit?
Yes
Replace the halogen heater
lamp.
Heater harness
connection
failure
5
Is the heater harness
connector connected to the
low-voltage power supply PCB
and fixing unit secure?
No
Reconnect the connectors
securely.
NOTE:
•
This problem will be cleared if leaving the printer power ON for ten minutes.
•
If the heater is cooled down sufficiently, this problem may be cleared by pressing the
Go
switch and
Set
switch together till the back light turns green and turning off the power
switch.
Be warned, however, that this operation will melt the fixing unit if the heater
is hot.
Summary of Contents for HL-1870N
Page 15: ...HL 1850 1870N SERVICE MANUAL xiii ...
Page 77: ...CHAPTER 2 INSTALLATION AND BASIC OPERATION 2 48 ...
Page 82: ...HL 1850 1870N SERVICE MANUAL 3 5 Fig 3 5 ...
Page 91: ...CHAPTER 3 THEORY OF OPERATION 3 14 Fig 3 15 ...
Page 101: ...CHAPTER 3 THEORY OF OPERATION 3 24 ...
Page 109: ...CHAPTER 4 DISASSEMBLY AND RE ASSEMBLY 4 2 ...
Page 131: ...CHAPTER 4 DISASSEMBLY AND RE ASSEMBLY 4 24 Fig 4 39 ...
Page 141: ...CHAPTER 4 DISASSEMBLY AND RE ASSEMBLY 4 34 Never touch the surface of the heat roller ...
Page 148: ...CHAPTER 4 DISASSEMBLY AND RE ASSEMBLY 4 41 ...
Page 158: ...CHAPTER 4 DISASSEMBLY AND RE ASSEMBLY 4 51 Fig 4 80 ...
Page 160: ...CHAPTER 4 DISASSEMBLY AND RE ASSEMBLY 4 53 Fig 4 82 ...
Page 167: ...CHAPTER 4 DISASSEMBLY AND RE ASSEMBLY 4 60 Fig 4 91 ...
Page 169: ...CHAPTER 4 DISASSEMBLY AND RE ASSEMBLY 4 62 Fig 4 93 ...
Page 172: ...CHAPTER 4 DISASSEMBLY AND RE ASSEMBLY 4 65 Fig 4 97 ...
Page 174: ...CHAPTER 4 DISASSEMBLY AND RE ASSEMBLY 4 67 3 27 Harness Winding Form ...
Page 183: ...CHAPTER 5 PERIODIC MAINTENANCE 5 8 ...
Page 186: ...HL 1850 1870N SERVICE MANUAL 5 11 ...
Page 194: ...CHAPTER 6 TROUBLESHOOTING 6 8 error in this chapter ...
Page 202: ...CHAPTER 6 TROUBLESHOOTING 6 16 ...
Page 205: ...HL 1850 1870N SERVICE MANUAL 6 19 ...
Page 210: ...CHAPTER 6 TROUBLESHOOTING 6 24 ...
Page 237: ...HL 1850 1870N SERVICE MANUAL 6 51 No Refer and compare with I 15 ...
Page 255: ...HL 1850 1870N SERVICE MANUAL 6 69 ...
Page 261: ...CHAPTER 7 HIDDEN FUNCTIONS 7 6 DRAM CHECK START START DRAM TEST Tests DRAM data ...
Page 270: ...HL 1850 1870N SERVICE MANUAL 7 15 ...
Page 271: ......
Page 272: ...Appendix 1 Connection Diagram HL 1850 1870N A 1 ...
Page 273: ...Appendix 2 Main PCB Circuit Diagram HL 1850 1870N 1 6 CODE LJ8453001 B512078CIR 1 6 A 2 NAME ...
Page 274: ...Appendix 3 Main PCB Circuit Diagram HL 1850 1870N 2 6 CODE LJ8453001 B512078CIR 2 6 A 3 NAME ...
Page 275: ...Appendix 4 Main PCB Circuit Diagram HL 1850 1870N 3 6 CODE LJ8453001 B512078CIR 3 6 A 4 NAME ...
Page 276: ...Appendix 5 Main PCB Circuit Diagram HL 1850 1870N 4 6 CODE LJ8453001 B512078CIR 4 6 A 5 NAME ...
Page 277: ...Appendix 6 Main PCB Circuit Diagram HL 1850 1870N 5 6 CODE LJ8453001 B512078CIR 5 6 A 6 NAME ...
Page 278: ...Appendix 7 Main PCB Circuit Diagram HL 1850 1870N 6 6 CODE LJ8453001 B512078CIR 6 6 A 7 NAME ...
Page 284: ...Appendix 13 High voltage Power Supply PCB Circuit Diagram A 13 NAME High voltage PS Circuit ...
Page 303: ...APPENDIX A 32 ...