Brother MFC-925 User Manual

FACSIMILE EQUIPMENT

SERVICE MANUAL

MODEL: FAX750/FAX770/FAX870MC

FAX-910/FAX-920/FAX-921/FAX-930/FAX-931 MFC-925/MFC970MC

form or by any means without permission in writing from the publisher.

Specifications are subject to change without notice.

PREFACE

This publication is a Service Manual covering the specifications, construction, theory of operation, and maintenance of the Brother facsimile equipment. It includes information required for field troubleshooting and repair--disassembly, reassembly, and lubrication--so that service personnel will be able to understand equipment function, to rapidly repair the equipment and order any necessary spare parts.

To perform appropriate maintenance so that the facsimile equipment is always in best condition for the customer, the service personnel must adequately understand and apply this manual.

This manual is made up of six chapters and appendices.

CHAPTER I. GENERAL DESCRIPTION CHAPTER II. INSTALLATION CHAPTER III. THEORY OF OPERATION CHAPTER IV. DISASSEMBLY/REASSEMBLY AND LUBRICATION CHAPTER V. MAINTENANCE MODE CHAPTER VI. ERROR INDICATION AND TROUBLESHOOTING

Appendix 1. EEPROM Customizing Codes Appendix 2. Circuit Diagrams

This manual describes the models and their versions to be destined for major countries. The specifications and functions are subject to change depending upon each destination.

CHAPTER I.

GENERAL DESCRIPTION

CONTENTS

1. EQUIPMENT OUTLINE............................................................................................I-1

1.1External Appearance and Weight.....................................................................I-1

1.2Components......................................................................................................I-1

2. SPECIFICATIONS.....................................................................................................I-2

1. EQUIPMENT OUTLINE

1.1 External Appearance and Weight

The figure below shows the equipment appearance and approximate dimensions.

Weight: Machine proper (excluding a ribbon cartridge) Approx. 4 kg (8.82 lbs.)

In package Approx. 6 kg (13.23 lbs.)

1.2 Components

The equipment consists of the following major components:

I - 1

2. SPECIFICATIONS

Model Name FAX750 FAX770

Engine Thermal transfer Thermal transfer Color Black (1395) White (1397) Transmission Speed (sec) 15 15 Modem Speed (bps) 9600 9600 Group Compatibility G3 G3 Input/Output Width 8.5"/8.5" 8.5"/8.5" ADF (pages) 10 10 Recording Paper Loadable 100 sheets 100 sheets Ribbon Life (Letter-size print) 250 pages (77 m) 250 pages (77 m) Starter Ribbon Life (Letter-size print) 100 pages (30 m) 100 pages (30 m) LCD Size 16 x 1 16 x 1 On-Screen Programming Yes Yes Super Fine Yes Yes Smoothing Yes Yes Gray Scale (levels) 64 by Dithered 64 by Dithered One Touch 8 8 Speed Dial 40 40 Telephone Index Yes Yes Speaker Phone Monitor Monitor Handset Yes Yes FAX/TEL Switch Yes Yes Distinctive Ring Detection* Yes Yes Caller ID* Yes Yes Call Waiting Caller ID* Yes Yes TAD Interface Yes Yes Enhanced Remote Activation Yes Yes Automatic Redial Yes Yes Next-FAX Reservation Yes Yes Multi-Resolution Transmission Yes Yes Polling Type Std/Seq Std/Seq Delayed Transmission 1-timer 1-timer Call Reservation Yes Yes Electronic Coverpage Yes - Super Yes - Super Call Back Message Yes Yes Activity Report Yes Yes TX Verification Report Yes Yes Memory Capacity (pages) 512 KB (20 pages) 512 KB (20 pages) ECM Yes Yes Broadcasting Yes Yes Quick-Scan Yes Yes Out-of-Paper Reception Yes Yes Multi-Copying w/ Sorting Yes Yes Enlargement/Reduction Ratio Yes (50-150%) Yes (50-150%) Multi-Transmission No No Confidential Mailbox No No Auto Reduction Yes Yes Message Center No No TAD Recording Time No No Fax Forwarding/Paging No Yes Fax Retrieval No Yes Fax-/Voice-on-demand No No Fax & Voice Mailbox No No Help List Yes Yes Missing Link/Multifunction Link Ready Ready Optional Memory No No Voice Alarm No No Others

* Check your local telephone company for availability of this service.

I - 2

Model Name FAX870MC MFC970MC

Engine Thermal transfer Thermal transfer Color White (1397) White (1138) Transmission Speed (sec) 9 9 Modem Speed (bps) 14,400 14,400 Group Compatibility G3 G3 Input/Output Width 8.5"/8.5" 8.5"/8.5" ADF (pages) 10 10 Recording Paper Loadable 100 sheets 100 sheets Ribbon Life (Letter-size print) 250 pages (77 m) 250 pages (77 m) Starter Ribbon Life (Letter-size print) 100 pages (30 m) 100 pages (30 m) LCD Size 16 x 1 16 x 1 On-Screen Programming Yes Yes Super Fine Yes Yes Smoothing Yes Yes Gray Scale (levels) 64 by Dithered 64 by Dithered One Touch 8 8 Speed Dial 40 40 Telephone Index Yes Yes Speaker Phone Full duplex (digital) Full duplex (digital) Handset Yes Yes FAX/TEL Switch Yes Yes Distinctive Ring Detection* Yes Yes Caller ID* Yes Yes Call Waiting Caller ID* Yes Yes TAD Interface Yes Yes Enhanced Remote Activation Yes Yes Automatic Redial Yes Yes Next-FAX Reservation Yes Yes Multi-Resolution Transmission Yes Yes Polling Type Std/Seq Std/Seq Delayed Transmission 1-timer 1-timer Call Reservation Yes Yes Electronic Coverpage Yes - Super Yes - Super Call Back Message Yes Yes Activity Report Yes Yes TX Verification Report Yes Yes Memory Capacity (pages) 512 KB (20 pages) 512 KB (20 pages) ECM Yes Yes Broadcasting Yes Yes Quick-Scan Yes Yes Out-of-Paper Reception Yes Yes Multi-Copying w/ Sorting Yes Yes Enlargement/Reduction Ratio Yes (50-150%) Yes (50-150%) Multi-Transmission No No Confidential Mailbox No No Auto Reduction Yes Yes Message Center Yes Yes TAD Recording Time 15 minutes 15 minutes Fax Forwarding/Paging Yes Yes Fax Retrieval Yes Yes Fax-/Voice-on-demand Voice-on-demand Voice-on-demand Fax & Voice Mailbox Yes Yes Help List Yes Yes Missing Link/Multifunction Link Ready Included Optional Memory No No Voice Alarm No No Others

* Check your local telephone company for availability of this service.

I - 3

Model Name FAX-910 FAX-920/921

Engine Thermal Transfer Thermal Transfer Color Black(1395) Black(1395)/White(1397/1138) Transmission Speed (sec) 15 15 Modem Speed (bps) 9600 9600 Group Compatibility G3 G3 Input/Output Width 8.5"/8.5" 8.5"/8.5" ADF (pages) 10 10 Recording Paper Loadable 100 sheets 100 sheets Ribbon Life (A4-size print) 235 pages 235 pages Starter Ribbon Life (A4-size print) 90 pages (30 m) 90 pages (30 m) LCD Size 16 X 1 16 X 1 On-Screen Programming Yes Yes Super Fine Yes Yes Smoothing Yes Yes Gray Scale (levels) 64 by Dithered 64 by Dithered One Touch 16 w/SHIFT KEY 16 w/SHIFT KEY Speed Dial 32 32 Telephone Index Yes Yes Speaker Phone Monitor Monitor Handset No Yes FAX/TEL Switch Yes Yes Caller ID Yes HOL/SWE/UK/FRA/NOR Yes HOL/SWE/UK/FRA/NOR Call Waiting Caller ID No No Distinctive Ringing No No TAD Interface Yes Yes Enhanced Remote Activation Yes Yes Automatic Redial Yes Yes Next-FAX Reservation Yes Yes Multi-Resolution Transmission Yes Yes Polling Type Sim/Sec/Del/Seq Sim/Sec/Del/Seq Delayed Transmission 3-timer 3-timer Call Reservation Yes Yes Electronic Coverpage Yes - Super Yes - Super Call Back Message Yes Yes Journal Report Yes Yes TX Verification Report Yes Yes Memory Capacity (pages) 512KB (20 pages) 512KB (20 pages) ECM Yes Yes Broadcasting Yes Yes Quick-Scan Yes Yes Out-of-Paper Reception Yes Yes Multi-Copying w/Sorting Yes Yes Enlargement/Reduction Ratio Yes (50-150%) Yes (50-150%) Multi-Transmission Yes Yes Confidential Mailbox No No Auto Reduction Yes Yes Message Manager No No TAD Recording Time No No Fax Forwarding/Paging Yes - Only Fax forwarding Yes - Only Fax forwarding Fax Retrieval Yes Yes Fax-/Voice-on-demand No No Fax & Voice Mailbox No No Help List Yes Yes MFL PRO for Fax Ready Ready Optional Memory No No Memo Manager No No Mute Key No Yes-music on hold; Green Sleeves Backup for Clock 9 hours 9 hours Output Tray Option (CT70) Option (CT70) Backup for Page Memory No No

I - 4

Model Name FAX-930/931 MFC-925

Engine Thermal Transfer Thermal Transfer Color Black(1395)/White(1397/1138) White(1138) Transmission Speed (sec) 9 15 Modem Speed (bps) 14,400 9600 Group Compatibility G3 G3 Input/Output Width 8.5"/8.5" 8.5"/8.5" ADF (pages) 10 10 Recording Paper Loadable 100 sheets 100 sheets Ribbon Life (A4-size print) 235 pages 235 pages Starter Ribbon Life (A4-size print) 90 pages (30 m) 90 pages (30 m) LCD Size 16X1 16X1 On-Screen Programming Yes Yes Super Fine Yes Yes Smoothing Yes Yes Gray Scale (levels) 64 by Dithered 64 by Dithered One Touch 16 w/SHIFT KEY 16 w/SHIFT KEY Speed Dial 32 32 Telephone Index Yes Yes Speaker Phone Full duplex (digital) Monitor Handset Yes Yes FAX/TEL Switch Yes Yes Caller ID Yes HOL/SWE/UK/FRA/NOR Yes HOL/SWE/UK/FRA/NOR Call Waiting Caller ID No No Distinctive Ringing No No TAD Interface Yes Yes Enhanced Remote Activation Yes Yes Automatic Redial Yes Yes Next-FAX Reservation Yes Yes Multi-Resolution Transmission Yes Yes Polling Type Sim/Sec/Del/Seq Sim/Sec/Del/Seq Delayed Transmission 3-timer 3-timer Call Reservation Yes Yes Electronic Coverpage Yes - Super Yes - Super Call Back Message Yes Yes Journal Report Yes Yes TX Verification Report Yes Yes Memory Capacity (pages) 512KB (20 pages) 512KB (20 pages) ECM Yes Yes Broadcasting Yes Yes Quick-Scan Yes Yes Out-of-Paper Reception Yes Yes Multi-Copying w/Sorting Yes Yes Enlargement/Reduction Ratio Yes (50-150%) Yes (50-150%) Multi-Transmission Yes Yes Confidential Mailbox No No Auto Reduction Yes Yes Message Manager Yes No TAD Recording Time 15 minutes No Fax Forwarding/Paging Yes - both Yes - Only Fax forwarding Fax Retrieval Yes Yes Fax-/Voice-on-demand Voice-on-demand No Fax & Voice Mailbox Yes No Help List Yes Yes MFL PRO for Fax Ready Included Optional Memory No No Memo Manager No No Mute Key Yes-music on hold; Green SleevesYes-music on hold; Green Sleeves Backup for Clock 15 hours 9 hours Output Tray Option (CT70) Option (CT70) Backup for Page Memory 6 hours No

I - 5

CHAPTER II.

INSTALLATION

CHAPTER III.

THEORY OF OPERATION

CONTENTS

1. OVERVIEW...............................................................................................................III-1

2. MECHANISMS..........................................................................................................III-2

2.1 Transmitting Mechanism (Feeding and scanning documents).........................III-2

2.1.1 Automatic document feeder (ADF)...........................................................III-2

2.1.2 Scanner.....................................................................................................III-3

2.2 Receiving Mechanism (Feeding paper and printing data).................................III-4

2.3 Power Transmission Mechanism......................................................................III-5

2.3.1 Structure of the gear train.........................................................................III-5

2.3.2 Description of planetary gear system........................................................III-6

2.3.3 Power transmission for four operation modes..........................................III-7

2.3.4 Power transmission route..........................................................................III-14

2.4 Sensors and Actuators......................................................................................III-16

3. CONTROL ELECTRONICS......................................................................................III-19

3.1 Configuration.....................................................................................................III-19

3.2 Main PCB..........................................................................................................III-20

3.3 NCU PCB..........................................................................................................III-22

3.4 Control Panel PCB............................................................................................III-24

3.5 Power Supply PCB............................................................................................III-25

1. OVERVIEW

*Not provided on the FAX-910.

III - 1

2. MECHANISMS

The facsimile equipment is classified into the following mechanisms:

n Transmitting Mechanism Feeding and scanning documents n Receiving Mechanism Feeding paper and printing data n Power Transmission Mechanism Switching the power transmission route n Sensors and Actuators

2.1 Transmitting Mechanism (Feeding and scanning documents)

The transmitting mechanism consists of the document stacker, automatic document feeder (ADF), document feeding related rollers, scanner, and document sensors. (For details about the sensors, refer to Section 2.4.)

For the drive power source, refer to Section 2.3.

2.1.1 Automatic document feeder (ADF)

If the operator sets documents on the stacker and starts the transmitting operation, the ADF (consisting of the separation roller and ADF parts) feeds those documents into the equipment, starting from the bottom sheet to the top, page by page. Each document advances to the scanner with the LF roller, and then it is fed with the document ejection roller.

III - 2

2.1.2 Scanner

The scanner uses a contact image sensor (CIS) unit which consists of an LED array illuminating documents, a self-focus lens array collecting the reflected light, a CIS PCB carrying out photoelectric conversion to output picture element data, and a cover glass on which a document advances. When the document passes between the document pressure bar and the cover glass, it is scanned.

III - 3

2.2 Receiving Mechanism (Feeding paper and printing data)

The receiving mechanism consists of the recording paper cover ASSY, paper feed roller ASSY, platen, thermal recording head, paper ejection roller, and sensors. (For details about the sensors, refer to Section 2.4.)

STEP 1: In the paper feeding mode If the equipment receives data, the control electronics activates the solenoid and rotates the motor

counterclockwise to drive the paper feed roller (and paper ejection roller). This pulls in a sheet of paper and feeds it until its leading edge reaches the point just before the printing position.

STEP 2: In the recording (platen drive & ribbon take-up) mode The control electronics deactivates the solenoid and rotates the motor clockwise to drive the platen

gear and the ribbon take-up gear as well as the paper ejection roller. This feeds the paper up to the printing position where the thermal recording head prints, as well as feeding the thermal ink ribbon.

STEP 3: In the paper ejection mode The same operation as for STEP 1 takes place so as to eject the paper.

III - 4

2.3 Power Transmission Mechanism

The equipment has a single drive motor whose power transmission route can be switched by the planetary gear systems and the solenoid. This switching allows the equipment to function in four operation modes (scanning, paper feeding/ejecting, recording, and copying modes). For the details about the planetary gear systems, refer to Subsection 2.3.2.

2.3.1 Structure of the gear train

All of the motor and gears are located at the left side of the equipment. As illustrated in the figure below (On the outer side of the drive unit), the rotational torque of the motor on the drive unit is transmitted via the gears on the drive unit to the gears on the main frame, to those on the control panel ASSY, and to those on the platen frame.

If gear 39/62 of the friction torque transmission ASSY ("V" in the figure below) rotates, gear 20 ("z") on the inner side of the drive unit also rotates. The rotational torque is further transmitted to the ribbon drive gear ("w") which drives the ribbon take-up gear ("a") on the ribbon cartridge, as shown in the figure below (On the inner side of the drive unit).

On the outer side of the drive unit and on the left sides of the platen frame, main frame and control panel ASSY

On the inner side of the drive unit

Gear Train

III - 5

2.3.2 Description of planetary gear system

The equipment uses the following three planetary gear systems:

- Sun gear 24/90 ("B" in the figure given on the previous page) and its planet gears

- Sun gear 65/60 ("K") and its planet gear

- Sun gear 24/28 ("O") and its planet gear This section describes the planetary gear system of sun gear 24/90 ("B"). It consists of sun gear

24/90, two planet gears 34, arm A, and arm B as shown below.

Planetary Gear System

If the motor rotates, sun gear 24/90 rotates so that the rotational torque is transmitted to the engagement between the sun gear and planet gears 34. Since the arms and planet gears are so designed that the moment of the arms is less than that of the planet gears, the arms turn around the center shaft in the same direction as sun gear 24/90.

If the planet gear(s) becomes engaged with any other gear so that the arm cannot turn furthermore, the rotational torque of sun gear 24/90 is transmitted to that planet gear. Accordingly, the planet gear starts rotation in the opposite direction of sun gear 24/90.

III - 6

2.3.3 Power transmission for four operation modes

Depending upon the solenoid ON/OFF state and the motor rotation direction, the planetary gear train switches the power transmission route for the four operation modes.

Solenoid ON/OFF state Motor rotation direction

III - 7

[ 1 ] Scanning mode (Solenoid: OFF, Motor rotation: Reverse)

In the scanning mode, the control electronics deactivates the solenoid. When the motor rotates in the reverse direction, the clutch lever turns counterclockwise with the compression spring so that its cutout becomes engaged with the stopper of arm A. Once arm A is locked, planet gear 34A ("J") will not be engaged with any other gear but simply idle.

The motor's rotational torque turns sun gear 24/90 ("B") clockwise so that planet gear 34B ("C") transmits the torque via gear "D" to gear "E" which drives the separation roller gear ("G") and gear "F." As gear "F" rotates, the LF roller gear ("I") and document ejection roller gear ("H") also rotate.

Arm A Locked by Cutout of Clutch Lever

Active Gears

III - 8

[ 2 ] Paper feeding/ejecting mode (Solenoid: ON, Motor rotation: Reverse)

In the paper feeding/ejecting mode, the control electronics activates the solenoid to release the stopper of arm A. When the motor rotates in the reverse direction, sun gear 24/90 ("B") rotates clockwise so that planet gear 34A ("J") transmits the torque via sun gear 65/60 ("K") and other gears to the paper feed roller gear ("T") and paper ejection roller gear ("R").

Since the stopper of arm B is blocked by section of the clutch lever, the planet gear 34B ("C") is merely idle without engaging with any other gear.

The rotational torque of the paper ejection roller gear ("R") is transmitted to the inner gear of the clutch gear ASSY ("S"). However, the outer gear does not rotate since it is engaged with the platen gear ("Y") that undergoes the heavy frictional torque of the platen. (This clutch gear ASSY works as a one-way clutch. If the outer gear is driven by the platen gear ("Y"), the inner gear also rotates. Refer to [ 3 ] Recording mode.)

Arm B Blocked by Section of Clutch Lever

Active Gears

III - 9

[ 3 ] Recording mode (Solenoid: OFF, Motor rotation: Forward)

In the recording mode, the control electronics deactivates the solenoid. When the motor rotates in the forward direction, the clutch lever turns counterclockwise with the compression spring so that its cutout becomes engaged with the stopper of arm A. Once arm A is locked, planet gear 34A ("J") will not be engaged with any other gear but simply idle.

The motor's rotational torque turns sun gear 24/90 ("B") counterclockwise so that planet gear 34B ("C") transmits the torque via sun gear 65/60 ("K") and other gears to the platen gear ("Y") and the paper ejection roller gear ("R").

If gear 39/62 ("V") of the friction torque transmission ASSY rotates, gear 20 ("z") on the inner side of the drive unit also rotates so as to drive the ribbon drive gear ("w") that rotates the ribbon take-up gear ("a") on the ribbon cartridge, as shown on the next page.

Arm A Locked by Cutout of Clutch Lever

Active Gears on the Outer Side of the Drive Unit and Left Side of the Platen Frame

III - 10

Active Gears on the Inner Side of the Drive Unit

III - 11

[ 4 ] Copying mode (Solenoid: ON, Motor rotation: Forward)

In the copying mode, the control electronics activates the solenoid to release the stopper of arm A from the clutch lever. When the motor rotates in the forward direction, sun gear 24/90 ("B") rotates counterclockwise so that planet gear 34A ("J") transmits the torque to the document scanner mechanism (e.g., the separation roller gear ("G"), LF roller gear ("I") and document ejection roller gear ("H")) and planet gear 34B ("C") transmits the torque to the recording mechanism (e.g., platen gear ("Y") and paper ejection roller gear ("R")).

If gear 39/62 ("V") rotates, gear 20 ("z") on the inner side of the drive unit also rotates so as to drive the friction torque transmission ASSY and ribbon drive gear ("w") that rotates ribbon take-up gear ("a") on the ribbon cartridge, as shown on the next page.

Arm A Released from Cutout of Clutch Lever

Active Gears on the Outer Side of the Drive Unit and on the Left Sides of the Platen Frame,

Main Frame and Control Panel ASSY

III - 12

Active Gears on the Inner Side of the Drive Unit

III - 13

2.3.4 Power transmission route

Rotation of the motor gear is transmitted as shown below.

Gears on the outer side of the drive unit and on the left sides of the platen frame, main frame and control panel ASSY

Gears on the inner side of the drive unit

A: Motor gear O: Sun gear 24/28 B: Sun gear 24/90 P: Planet gear 34P C: Planet gear 34B Q: Gear 19/38 D: Gear 40 R: Paper ejection roller gear E: Gear 18/54 S: Clutch gear ASSY F: Gear 37 T: Paper feed roller gear, Gear 43 ASSY G: Separation roller gear U: Planet gear 34C H: Document ejection roller gear V: Friction torque transmission ASSY (Gear 39/62) I: LF roller gear w: Ribbon drive gear (Gear 25) J: Planet gear 34A X: Gear 22/28 K: Gear 65/60 Y: Platen gear (Gear 25/27) L: Gear 50 z: Gear 20 M: Gear 63 a: Ribbon take-up gear on the ribbon cartridge N: Gear 44/38

III - 14

[ 1 ] Scanning Mode (Solenoid: OFF, Motor rotation: reverse)

[ 2 ] Paper Feeding/Ejecting Mode (Solenoid: ON, Motor rotation: reverse)

[ 3 ] Recording Mode (Solenoid: OFF, Motor rotation: forward)

[ 4 ] Copying Mode (Solenoid: ON, Motor rotation: forward)

III - 15

2.4 Sensors and Actuators

This equipment has five photosensors and two mechanical switches as described below.

Sensor name Type Located on

Document front sensor Photosensor Control panel PCB ASSY Document rear sensor Photosensor (PI2) Main PCB

Paper-edge sensor Photosensor (PH1) Sensor PCB Paper ejection sensor Photosensor (PH2) Sensor PCB

Ribbon sensor Photosensor (PI1) Main PCB Cover sensor Mechanical switch (SW1) Main PCB Hook switch sensor* Mechanical switch (SW1) Hook switch PCB

• Document front sensor which detects the presence of documents.

• Document rear sensor which detects the leading and trailing edges of pages to tell the control circuitry when the leading edge of a new page has reached the starting position and when the scan for that page is over.

• Paper-edge sensor which detects the leading and trailing edges of paper and the presence of paper as well as detecting whether the paper front cover is closed.

• Paper ejection sensor which detects whether a paper jam has occurred.

• Ribbon sensor which detects whether the ink ribbon is loaded.

These photosensors are a photointerrupter consisting of a light-emitting diode and a light-sensitive transistor. Each of them has an actuator separately arranged (see the following pages) except that the paper-edge sensor has two actuators for sensing the paper and the paper front cover. When an actuator is not activated, its black end lies in the path of light issued from the light-emitting diode and interrupts its light so that the emitted light does not enter the light-sensitive transistor. If a document, paper, or ribbon comes in so as to activate the actuator, the actuator's black end goes out of the light path and the emitted light enters the light-sensitive transistor. This way, the sensor detects the presence of documents, paper, or ink ribbon.

• Cover sensor which detects whether the recording paper cover ASSY is closed.

• Hook switch sensor* which detects whether the handset is placed on the handset mount.

The cover sensor has an actuator ASSY (consisting of two actuators and a spring). If you open the recording paper cover ASSY, the actuator ASSY pops up to release the sensor.

*Not provided on the FAX-910.

III - 16

Location of Sensors and Actuators (1)

III - 17

+ 188 hidden pages