HL-1850/1870N SERVICE MANUAL
6-45
I-13
Image distortion
Possible cause
Step
Check
Result
Remedy
Laser unit
installation
1
Is the laser unit secured to the
frame incorrectly?
(Check if there is any play.)
Yes
Secure the unit correctly and
tighten the screws.
Scanner LD
emission failure
Scanner motor
rotation failure
2
Is the laser diode or the
scanner motor defective?
Yes
Replace the laser unit.
Scanner
connection
failure
3
Is the scanner harness
connected properly?
(Check if it is coming loose.)
No
Connect the harness correctly.
I-14
Faint print
Print out test print out test print out test Print out test print o
Print out test print o
Print out test print out test print out test Print out test print o
Print out test print o
Print out test print out test print out test Print out test print o
Print out test print o
Print out test print out test print out test Print out test print o
Print out test print o
Print out test print out test print out test Print out test print o
Print out test print o
Print out test print out test print out test Print out test print o
Print out test print o
Print out test print out test print out test Print out test print o
Print out test print o
Print out test print out test print out test Print out test print o
Print out test print o
Print out test print out test print out test Print out test print o
Print out test print o
Print out test print out test print out test Print out test print o
Print out test print o
Print out test print out test print out test Print out test print o
Print out test print o
Print out test print out test print out test Print out test print o
Print out test print o
Print out test print out test print out test Print out test print o
Print out test print o
Print out test print out test print out test Print out test print o
Print out test print o
Print out test print out test print out test Print out test print o
Print out test print o
Print out test print out test print out test Print out test print o
Print out test print o
Print out test print out test print out test Print out test print o
Print out test print o
Print out test print out test print out test Print out test print o
Print out test print o
Print out test print out test print out test Print out test print o
Print out test print o
Print out test print out test print out test Print out test print o
Print out test print o
Print out test print out test print out test Print out test print o
Print out test print o
Print out test print out test print out test Print out test print o
Print out test print o
Print out test print out test print out test Print out test print o
Print out test print o
Print out test print out test print out test Print out test print o
Print out test print o
Print out test print out test print out test Print out test print o
Print out test print o
Print out test print out test print out test Print out test print o
Print out test print o
Possible cause
Step
Check
Result
Remedy
Printer
installation
1
Is the printer placed
horizontally?
No
Place the printer on a flat
surface.
Toner cartridge
2
Does the problem happen
immediately after replacing the
toner cartridge with a new
one?
Yes
Remove and carefully shake the
toner cartridge horizontally.
Scanner window
dirty
3
Is the scanner window dirty?
Yes
Clean the scanner window with
a soft dry cloth.
Laser unit failure
4
Is the problem solved by
replacing the laser unit?
Yes
Replace the laser unit.
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 ...