HL-1850/1870N SERVICE MANUAL
6-29
5. MALFUNCTIONS
When taking countermeasures for malfunctions as described in this section, check connectors
for contact failure before measuring the voltage at the specified connector pins.
M-1
No AC power supplied
Possible cause
Step
Check
Result
Remedy
Supply voltage
1
Is the correct voltage present
at the outlet?
No
Inform the user that the
correct voltage is not supplied
at the outlet.
Power plug
2
Is the power cord securely
plugged into the outlet?
No
Plug the power cord securely
into the outlet.
Fuse (F1, F2)
3
Is the fuse blown?
Yes
If the fuse blows again
immediately after replacing
the low-voltage power supply
PCB, check that there is not a
short circuit somewhere in the
AC power supply line.
Wiring
4
Unplug the power supply plug.
Is there a broken wire between
the AC input connector of the
low-voltage power supply and
the power plug?
Yes
Replace the AC power cord.
M-2
No DC power supplied
Possible cause
Step
Check
Result
Remedy
AC power
supply
1
Is AC power supplied between
connectors CN1-L and CN1-N
when the power plug is
plugged into the outlet?
No
Follow the same check
procedure of M-1 No AC
power supplied.
Wiring, DC load
2
Turn off the power switch and
disconnect the P3 and P5
connectors on the engine PCB.
Turn on the power again.
Measure the voltages between
the terminals. Do the
measured voltage satisfy the
prescribed valued in the table
below?
Yes
Turn off the power switch,
reconnect the connector and
turn the power switch on
again. If the protector circuit
is activated, check the
connector, the wiring from the
connector, and the DC load.
Low-voltage
power supply
PCB
3
PCB
+ lead pin - lead pin
Voltage
Engine
P5-2
P5-3
Approx. 24V
P3-10
P3-9
Approx. 5V
No
Replace the low-voltage
power supply PCB.
WARNING
If you analyze malfunctions with the power plug inserted into the power outlet, special
caution should be exercised even if the power switch is OFF because it is a single pole
switch.
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 ...