Brother MFC-370MC User manual

FACSIMILE EQUIPMENT
SERVICE MANUAL
MODEL: FAX-270MC/290MC/520DT/520MC
MFC370MC/390MC

NOTE
This Service Manual presents specifications, theory of operation, and maintenance
information which pertain exclusively to the FAX-270MC/290MC/520DT/520MC/
MFC370MC/390MC. For additional descriptions common to both FAX-270MC/
290MC/520DT/520MC/MFC370MC/390MC and FAX[phone]/HOME FAX,
please refer to the FAX[phone]/HOME FAX Service Manual.

CHAPTER I.
GENERAL DESCRIPTION

2. SPECIFICATIONS
Model
Color
Modem Speed
CodingMethod
TransmissionSpeed
CCITT Group
Input/OutputWidth
HoldKey
AutomaticCutter
ADFCapacity
Anti-curlSystem
RollPaperSize(Standardthermalf_ermaPLUS)
LCDSize
On-screenProgramming
MemoryCapacity
SuperRne
Smoothing
GreyScale (levels)
One-touchDialing
SpeedDialing
TelephoneIndex
SuperTelephoneIndex
Speaker Phone
Fax/TelSwitch
TADInterface
Enlargement/Reduction
EnhancedRemoteActivation
DistinctiveRinging(FAXAbility)
Next-faxReservation
Help
Caller ID (CallerDisplay)
AutomaticRedialing
AutoReduction
Multi-resolutionTransmission
Polling
DelayedTransmission
DelayedPolling
Coverpage
CallReservation
Call-backMessage
ActivityReport
AutoCNG Detection(New)
TransmissionVerificationReport
ECM
Broadcasting
QuickScanning
Out-of-paperReception
Multi Copy
Multi Transmission
PCl (Missing link)
Confidential Mailbox
Fax Forwarding
Fax-on-demand
Fax Retrieval
ICM RecordingTime 15
Memo/2-wayRecording
Page Memory Yes,
Paging
PersonalFaxMail box(5)
PersonalVoice Mail Box(5)
RemoteControl
TADType
TollSaver
Voice-on-demand
FAX-270MC/290MC
Black (1395)
14400 bps
MH
9 sec.
G3
Max. 216/216 mm
Yes
Yes
10pages
Yes
98' (1" Core)
16xl
Yes
512 KB
Yes
Yes
64 by Dithered Method
5 locations
50
Yes
No
Yes
Yes
Yes
No
Yes
Yes
Yes
Yes,Simple
Yes
Yes
No
Yes
Yes (No secure polling)
Yes,3 timers
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes, 20 pages
Yes
No
Yes
No
Yes
No
Yes
minutes
Yes
20 pages
Yes
Yes
Yes
Yes
DSPtype
Yes
Yes
MFC370MC
White (1138)
Same as left
Yes, Included
!MFC390MC
White (1138)
Same as left
Same as left
I-2
Same as left
Yes, Included w/OCR

Model
Color
Modem Speed
Coding Method
Transmission Speed
CCITT Group
Input/Output Width
Hold Key
Automatic Cutter
ADF Capacity
Anti-curl System
RollPaperSize(StandardthermalfTnermaPLUS)
LCDSize
On-screenProgramming
MemoryCapacity
SuperRne
Smoothing
Gray Scale (levels)
One-touchDialing
Speed Dialing
TelephoneIndex
SuperTelephoneIndex
Speaker Phone
Fax/TelSwitch
TAD Interface
Enlargement/Reduction
EnhancedRemoteActivation
DistinctiveRinging(FaxAbility)
Next-faxReservation
Help
Caller ID (CallerDisplay)
AutomaticRedialing
Auto Reduction
Multi-resolutionTransmission
Polling
DelayedTransmission
Delayed Polling
Coverpage
CallReservation
Call-backMessage
ActivityReport
Auto CNG Detection(New)
TransmissionVerificationReport
ECM
Broadcasting
Quick Scanning
Out-of-paperReception
MultiCopy
MultiTransmission
PCl (Missinglink)
ConfidentialMailbox
PowerFailureDialing
FaxForwarding
F_.x-on-demar_
Fax Retrieval
ICM Recording "rime
Memo/2-way Recording
Page Memory
Paging
Personal Fax Mail box (5)
Personal Voice Mail Box (5)
Remote Control
TAD Type
Toll Saver
Voice-on-demand
FAX-520DT/520MC
Black(1395)/White(1397)*
14400 bps
MH
9sec.
G3
Max.216/216
Yes
Yes
10 pages
Yes
30 m(1' Core)
16xl
Yes
512 KB
Yes
Yes
64 byDitheredMethod
5
50 locations
Yes
Yes,50 locations
Yes(onlyfor FAX-520MC)
Yes
Yes
No
Yes
Yes (onlyfor FAX-520MC)
Yes
Yes,Simple
YesforUK/NLD/SWE/NZ
Yes
No
Yes
Yes(w/secure polling)
Yes,3 timers
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes,20 pages
Yes
No
Yes
No
Yesfor UK/BEL
Yes
No
Yes
15 minutes
Yes
Yes,20 pages
Yes
Yes
Yes
Yes
DSPtype
Yes
Yes
I-3
* FAX-520DT: Black (1395)
FAX-520MC: White (1397)

CHAPTER Ill.
THEORY OF OPERATION

IIIII_1
I I
o., ;;:: ....
I • I _ "
Main PCB Circuit Diagram 1/5
OSW1, hook switch sensor (microswitch)
(_) SW2, cover switch sensor (microswitch)
(_) SW3, paper empty sensor (microswitch)
(_) Reset IC which turns on at the powering-on sequence and at any of the reset opera-
tions.
(_) Connector for the control panel
(_) FAX engine (ASIC) which integrates a CPU, digital portion of a MODEM and gate array
for managing the I/Os, memories, and drivers.
(_ XT2, oscillator which oscillates at 16 MHz for the CPU.
(_) XT1, oscillator which oscillates at 32.768 kHz for the calendar clock.
(_ XT3, oscillator which oscillates at 57.6 MHz for the MODEM.
_) Connector for the cutter HP sensor
III - 19

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®
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Main PCB Circuit Diagram 2/5
(_) E2pROM (16k x I bit)
(_ ROM (256k x 8 bits. Note that the qualification machines for demonstration have a 2-
megabit ROM.)
(_) DRAM (512k x 8 bits)
Q Backup circuit for the calendar clock of the control panel and DRAM.
Ill - 20

'_ I I [ I
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,,,
1,I
I I
Main PCB Circuit Diagram 315
® Connector for the CIS
@
®
®
(_)-1:
®-2:
O'3:
®-4:
Power for the ClS LED array
Clock output
Trigger signal output. One shot of this signal triggers a line of scan.
LED control signal output circuit which controls the intensity of the CIS LED ar-
ray.
Input of video data (VID) to the FAX engine
Clamp circuit that gives the bias level to the amplifier of the VlD input circuit ac-
cording to the CLAMP and CLPWM signals issued by the CPU (that monitors
the current video data input) for compensating the DC component of video sig-
nals for the next scan line
Connector for the thermal recording head
(_)-1: Power 26V for the thermal recording head
(_-2: Thermister signals which are normalized by the resistor network and fed to the
FAX engine
(_-3: Strobe signals
0-4: Data signals
_-5: Power 5V for the logic circuit of the thermal recording head
Connector for the motor
Connector for the solenoid (that switches the power transmission)
III - 21

Transistor array which consists of seven transistors
(_)-1: Transistors that control the rotation direction of the motor _._.u_uing to me MM4
through MM1 signals.
(_)-2: Transistor that turns on and off the solenoid.
The combination of the solenoid state and the motor rotation direction deter-
mines to which the motor torque should be transmitted, the cutter, the document
feeding mechanism, or the paper feeding mechanism.
(_-3: Transistor that turns on and off the CR1 relay for switching on and off the +26V
power source to the thermal recording head.
(_)-4: Transistor that turns on and off the CML relay.
(_) Document front and rear sensor circuitry that is active only while the SEON signal is on.
The LEDs for the sensors are driven by the +26V source.
(_)-1: PH1, document rear sensor
(_-2: PH2, document front sensor
! :
III -22

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_ ,,_"(_._;,...... ' ®- i::ii!,i! :.::.,
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NCU
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Main PCB Circuit Diagram 415
0 Connector for the power supply PCB
O-1: CR1, recording head on/off relay
(_) 3-terminal regulator which eliminates unstabilized components of the +9V source to
generate stabilized 5V source.
(_ Connector for the NCU
(_)-1: Power for the NCU
(_)-2: Signals to the telephone
(_)-3: Signals from the telephone
(_) Analog signal selectors
(_)-1: Selects either input signals from the handset or those from the MODEM.
(_)-2: Selects either RL1 or RL2 signals inputted from the communications network.
(_)-3: Selects sound signals (e.g., alarm beeps, key clicks and ringer sounds) gener-
ated by the FAX engine, hands-free monitor signals, or voice playback signals.
(_ Analog signal selectors
(_)-1 Selects either signals gated by (_-2 or voice signals coming from the handset.
(_)-2 Selects either signals gated by (_-2 or voice playback signals.
(_-3 Selects either signals gated by (_)-2 or hands-free monitor signals.
(_) Amplifier circuit for signals outputted from the MODEM
(_) Analog front end IC which processes the analog I/O signals from/to the MODEM.
(_) Amplifier & shaper circuit for signals inputted from the communications network.
(_) Telephone circuit for transmitting signals.
III - 23

@
@
@
Speaker i:tlwlpli|iel L;ircult which _lHpIitles _,ounds Issue(] lrom the c_bovu ,_l_dlOg slgi_dl
selector (_)-3 and feeds them to the speaker.
Connector for the speaker
Speaker volume control circuit
(_)-1:VOL1 OFF
_)-2: VOL2. OFF
_)-3:VOL3 OFF
Speaker volume High
ON ON
OFF ON
OFF ON
Medium Low (ON: Closed OFF: Opened)
III- 23 - 1

-- _J_ , L.L v I ____ __
@
IIIItI
Main PCB Circuit Diagram 515
(_) Microphone connector
(_) Amplifier and shaper circuit for signals inputtedfrom the microphone.
(_) Analog front end IC which processes the analog I/O signals from/to the MODEM.
(_) Amplifier circuitfor signals outputted from the MODEM.
III - 23 - 2

3.3 NCU PCB
The NCU PCB switches the communications line to telephone or Ioullt-_nML)DI-M, u_+derthe
control of the main PCB.
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P*.
T_OFF
C,
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+..+ _.I," l¢lll
.++O--I.I.L-_c_
I,+O.--_--M_
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7, MC: METALLIZIID POLYESTER FILMCAPACITOR
e, PC: POLYESTERFILMCAPACITOR
S. CC: CERAMICCAPACITO_
A. EC: ALUMINUMELECTROLYTIC CAPACITOR
$. COMPONENTS IN PARENTHESES NOTTO BEMOUNTED¸
2, UNLESSOTHERWISE SPECIFIEO,THE VOLTAGERESISTANCE OFCAPACITORS IS 2SVOR S0V+
1. UNLESSOTNERWIS£ SPECIFIED, POWER CONSUMP11ONOF RE_ASTORS_S1/4W
• , I,I, "1 IsIe"
NCU PCB Circuit Diagram (U.S.A. versions)
(_ Surge absorber
(_) Line relay (CML relay)
(_) Line transformer
(_) Circuit related to the line transformer
(_) High-impedance transformer circuit
(_) Calling signal detector
(_) Loop current detector
(_) Diat pu_se generator
(_) Telephone circuit
_) Reference voltage generation circuit for the operational amplifiers in (_) and (_).
@ Noise filters
Ill - 24

CHAPTER I¥.
DISASSEM BLY/REASSEMBLY
AND LUBRICATION

1.2 HUM L;over una _atle_y ASSY
(1) Insert the tip of the spring huuK a[ tile ueill.e[ ur lell. hal! ol tr_e luL;Klng arm as shown
below, then lift up the hook to release and move the ROM cover to the right.
(2) Slightly lift up the ROM cover and disconnect the battery harness from the main PCB,
then take out the ROM cover together with the battery ASSY.
(3) Remove the battery ASSY from the ROM cover.
Battery ASSY
Spdnghook ROM cover
Locking arm
Battery harness
(Hook this area.)
Main PCB
Battery connector
IV-6

(4) Io taKe out the main PUb or the power supply PCB in Section 1.18, unhook the battery
harness core and cutter HP sensor harness core from bosses "C" and "D," respectively,
at this stage.
Boss"C"
(Unhook the Dowersupply
h#rness core from here.) Powersupplyharness
I (Rear)
Cutter HP sensor
harness
Main PCB
Motor harness
Boss_D"
(Unhook thecutterHPsensor
harness corefrom here.)
'"F" Rib "E" Resistors
Solenoid Recording
harness head harness
CIS harness
Electrolytic
capacitor
PE sensor actuator
IV-6-1

1.4 Control Panel ASSY
(1) Disconnect the main-panel harness and the main-mike harness from the main PCB,
and then take out those harnesses from the groove of the main frame.
(2) Slightly bring the control panel ASSY back up towards you so that you can release the
panel lock arm from the boss of the main frame. Pull out the panel lock arm to the left
and fully open the control panel ASSY.
Panellockarm Boss
,_, Control panel ASSY
Main-panel harness
and main-mike
harnessrouted
throughthegroove
Main-mike harness
Main-panel harness
Main-mike harness
Main-panel harness
(Main PCB)
IV -8

(3) Push the control panel ASSY back and remove it.
Control panel ASSY
Main-mike harness
Main-panelharness
Panel lockarm
•Reassembling Notes
•Make sure that the main-panel harness and main-mike harness are routed through the
groove provided on the recording paper cover and are kept in place with the panel lock
arm, as illustrated on page IV-11.
F¢-8-1

1.5 Recording Paper Cover, Panel Rear Cover, Control Panul and Microphone
(1) Place the control panel ASSY upside down.
(2) Turn the panel lock arm until the cutout provided in it becomes aligned with the bo_ OT
the arm support, then pull it out to the left.
(3) Remove the two screws "a" from the recording paper cover and lift up the rear edge of
the cover.
(4)
(5)
(6)
(7)
Remove the ADF parts (ADF film, separator and leaf spring), using the spring hook and
a flat screwdriver. Once removed, they will become unusable and new parts should
have to be put back in.
Remove the four screws "b" from the panel rear cover, then unhook the latch "L" and lift
up the cover.
To take out the control panel PCB and the FPC key, unlock the LCD cable connector
and disconnect the LCD flat cable.
To separate the FPC key from the control panel PCB, unlock the FPC key connector
and disconnect the FPC key. . ,
Arm supped
Recording
papercover
Na.
?
Panel lock arm
ADF parts (_. ADF film
Leaf spring _ "b"
"b"_ "'
Panelrearcover
Main-panel harness
Latch "L"
FPC key
FPC key connector
Control panel PCB
LCD cable connector
Microphone
Control panel
LCD flat cable
LCD
IV- 9