Brother HL-820 Service Manual page 3

This service manual contains basic information required for after-sales service of the laser printer
(here- in-after referred to as "this machine" or "the printer"). This information is vital to the service
technician to maintain the high printing quality and performance of the printers.
This service manual covers the HL-820, 1020, 1040 and 1050 laser printers. (Note that any figures
for the printer body are based on the HL-1040 printer.)
This manual consists of the following chapters:
CHAPTER I : FEATURES AND SPECIFICATIONS
Features, specifications, etc.
CHAPTER II : THEORY OF OPERATION
Basic operation of the mechanical system, the electrical system and the electrical
circuits, and their timing information.
CHAPTER III : DISASSEMBLY AND REASSEMBLY
Procedures for disassembling and reassembling the mechanical system.
CHAPTER IV : MAINTENANCE AND TROUBLESHOOTING
Reference values and adjustments, troubleshooting image defects, troubleshooting
malfunctions, etc.
APPENDICES :SERIAL NO. DESCRIPTIONS, CONNECTION DIAGRAMS, PCB CIRCUIT
DIAGRAMS.
Information in this manual is subject to change due to improvement or re-design of the product. All
relevant information in such cases will be supplied in service information bulletins (Technical
Information).
A thorough understanding of this printer, based on information in this service manual and service
information bulletins, is required for maintaining its print quality performance and for improving the
practical ability to find the cause of problems.
PREFACE