TABLE OF CONTENTS
iii
4.2 Load Paper Manually......................................................................................................2-10
4.3 Two Side Printing (Manual Duplexing)............................................................................2-11
4.3.1 To print on both sides of the paper from the paper cassette ............................................2-11
4.3.2 To print on both sides of the paper from the manual feed slot.......................................... 2-12

5. CONTROL PANEL OPERATION................................ ...........................................2-13

5.1 Ready (Paper) LED Indications......................................................................................2-13
5.2 Data (Toner) LED Indications.........................................................................................2-14
5.3 Drum LED Indications.....................................................................................................2-14
5.4 Alarm LED Indications....................................................................................................2-14
5.5 Control Panel Button Operations....................................................................................2-15
5.6 Other Control Features...................................................................................................2-15
5.6.1 Sleep mode................................................................ .......................................................2-15
5.6.2 Test print mode................................ .................................................................................2-16

6. NETWORK BOARD OPERATION (FOR HL-1270N ONLY) ..................................2-17

6.1 Preparing the BR-net Board............................................................................................2-17
6.1.1 Connect the Ethernet cable .............................................................................................. 2-17
6.1.2 Install the BRAdmin32: configuration utility (for Windows 95/98/NT 4.0 users only) ........2-17
6.1.3 Print configuration page................................ ....................................................................2-18
6.2 Functions........................................................................................................................2-18
6.2.1 LED functions................................................................................................ ....................2-18
6.2.2 Factory default setting................................................................................................ .......2-18
CHAPTER 3 THEORY OF OPERATION................................................. 3-1

1. ELECTRONICS ................................................................ ................................ .......3-1

1.1 General Block Diagram.....................................................................................................3-1
1.2 Main PCB Block Diagram.................................................................................................3-4
1.3 Main PCB..........................................................................................................................3-7
1.3.1 ASIC................................................................................................................................ ....3-7
1.3.2 ROM................................................................................................................................ ..3-10
1.3.3 Flash ROM................................................................ ........................................................3-12
1.3.4 DRAM................................................................................................................................ 3-12
1.3.5 Optional RAM................................................................ ................................ ....................3-14
1.3.6 Optional serial I/O ............................................................................................................. 3-15
1.3.7 PCI bus ............................................................................................................................. 3-15
1.3.8 EEPROM................................................................................................ ........................... 3-16
1.3.9 Reset circuit ...................................................................................................................... 3-16
1.3.10 Engine I/O................................................................................................ .........................3-17
1.4 Engine PCB ....................................................................................................................3-18
1.5 BR-net PCB (for HL-1270 only)......................................................................................3-18
1.6 Power Supply..................................................................................................................3-19
1.6.1 Low-voltage Power Supply ............................................................................................... 3-19
1.6.2 High-voltage Power Supply............................................................................................... 3-20

2. MECHANICS ................................................................ ................................ .........3-21

2.1 Overview of Printing Mechanism....................................................................................3-21
2.2 Paper Transfer................................................................................................................3-23
2.2.1 Paper supply................................ .....................................................................................3-23
2.2.2 Paper registration................................................................................................ ..............3-23