5-26 Samsung Electronics
Circuit Description
5-3 OPE PBA
5-3-1 SUMMARY
OPE Board i s separated functionally from the main
board and operated by the micom(Z8601) in the
board. OPE and the main use UART (universal
asynchronous receiver/transmitter) channel to
exchange information. OPE reset can be controlled by
the main. OPE micom controls key-scanning and LCD
and LED display, detects documents and
senses SCAN position. If there occurs an event in OPE
(such as key touch and sensor level change), it sends
specific codes to the main to respond to the situation
and the main analyzes these codes and operates the
system. For example, if the main is to display
messages in OPE, the main transmits data through
U A RT line to OPE according to the
designated format and OPE displays this on LCD,
LED. OPE’s sensing is also transmitted to the main
through UART line and then the main drives
necessary operation.
5-3-2
OPE PBA consists of U1 (MICOM, Z8601), LCD, key
matrix, LED indicators, SCAN position sensor and the
document detect sensor. Refer to OPE Schematic
Diagram and Wiring Diagram sections of this manual.
• Signals fr om the key matrix are deliver ed to U1X/Y
input pin group (P1-x).
• U1 pin 4 (TX D ATA) is the UART code sent to
MAIN PBA.
• Display from the contro ller is r eceived at U1 pin 5
(RX DAT A).
• LCD drive signals are sent fr om U1 P2-x pin group,
P3-4~P3-6 pins.
• Machine status LED drive signals are sent fr o m U 1
P0-x pin group.
• Document detect sensor output is received at U1
pin 33 (P3-3).
• Scan position sensor output is r eceived at U1 pin 43
(P3-1).
OPE BLOCK DIAGRAM
Samsung Electronics 5-27
5-4 LIU PBA
5-4-1 Summary
LIU(Line Interface Unit) circuit added only to
Msys 5200, Msys 5150, SF-5800, SF-5800P is
controlled by the main cir c uit.
It monitors telephone line and helps interface between
the system and the telephone line. It uses
1-LIU(STI9510) to control the whole LIU,
MODEM/LINE INTERFACE, RING SIGNAL
DETECTOR, DIALER, LINE CURRENT
DETECTOR, and SERIAL INTERFACE.
5-4-2 Modem/Line Interface
This is the path thr ough which transmitted and
received data of modem is put in and out.
• CML1 Relay: It divides telephone line into
external telephone and fax.
• U3-3 TIT(Transformer Input from Transformer):
This single ended input receives image signals fro m
modem through transformer T2 and
transmits them on telephone line.
• U3-40 ROT(Receive Output Transformer): This
output transformer receives signals on telephone
line and delivers them to modem through
transformer T1. It has AC impedance of 10Kohm or
over.
• AC impedance: Normal operation range of
U3(STI9510) is fro m 15mA to 100mA. DC
characteristics depend on the voltage of U3-37
LI(Line Input) terminal and the voltage of
resistance R48 between U3-37 LI(Line Input)
terminal and U3-39 LS terminal.
5-4-3 Ring Signal Detector
• U3-28(MO) terminals are ring signal output
terminals. Q4 and Q5 put out ring signals and drive
Piezzo, but Msys 5200, Msys 5150, SF-5800,
SF-5800P does not use Piezzo. It has only the
functions related to ring detection such as driving
the photocoupler of U4 and delivering ring signals
to MFP
controller of the main.
5-4-4 Dialer
5-4-4-1. MF DIAL
• Default mode it is set in DP. Y ou can change it to
MF mode by contro l of MF P contr oller.
• MF signal can be measured a t (tone level of low
group: typical - 14dBm) U3-4 MFO(DTMF
Generator Output). The signal is adjustable by R40,
R41 and C29. The adjusted signal enters U3-9 MFI
(DTMF Amplifier Input) and is amplified to be
transmitted on telephone line.
• U3-39 LS(Line Current Sense Input) terminals show
the final signals transmitted to telephone line.
5-4-4-2. DP DIAL
• If U3-2(DMS) is made Vcc by R42, it is set at 33:67
D P signal. If it is made Vss by R43, it is set at DP
signal. This product is set at DP signal.
• D P signal is made by U3-27(DPn) terminals. This
signal turns on/off Q1. The signal made at that time
turns on/off Q2, which interrupts DC
current on telephone line and puts out pulse
signal on telephone line.
• U3-35 CS terminals : It makes Make Resistance by
shorting telephone line with Vss during Make
period of DP d ial.
5-4-5 Line Current Detector
• When CML1 relay connects telephone line, U3
(STI9510) of LIU board and MFP contr oller of the
main board (U16) start communication through
U A RT. U3 of LIU board sends signal that includes
information of line curr ent value, whenever it
receives orders or data fr om U16 of the main board.
Circuit Description
5-28 Samsung Electronics
Circuit Description
5-4-6 Serial Interface
• This part does serial communication with MFP
controller of the main boar d (MAIN PBA:U16) that
controls the whole system. It contr ols LIU by giving
and taking all control orders and line
status.
• U3-11 RxD : Schmitt Trigger input, Receiving
terminal.
• U3-29 TxD : Open Drain output terminal
• Standard U ART communication
- Baud Rate : 9600bps
- Start, Stop bit : 1bit each
- Data bits : 8 bit
- Parity bit : none
5-4-7 MAJOR FUNCTIONS OF PARTS
1) U3 : STI9510
- Key part of LIU board. Speech Network,
Dialer, Ringer and UART a re built in one IC
package.
2) U5 : PC817
- Photo coupler. It enables UART of
U3(STI9510) to receive contr ol signal or
dialing information fro m M F P contr oller of
the main board (U15).
- Insulation Detween prinary and secondany
cir cuit part.
3) U6 : PC817
- Photo coupler. It enables UART(U3-29:TxD)
of U3(STI9510) to deliver telephone line
status or r esponse signal about contro l
signal or dialing information fro m LIU MFP
controller of the main boar d (U15).
- Insulation Detween prinary and secondany
cir cuit part.
4) U4 : PC817
- It senses and delivers ring signal to the main
board.
- Insulation Detween prinary and secondany
cir cuit part.
5) U2 : PC814
- It senses hook-off (Line connection) of the
external telephone and delivers it to the main
board.
- Insulation Detween prinary and secondany
cir cuit part.
6) BD1 : BRIDGE DIODE
- Regardless of the polarity of DC power
fr om telephone line, the voltage put out on
Pin.1 has always + polarity against pin
Pin.2. So DC loop forms always in the same
dir ection r egardless of the polarity of the
telephone line.
7) T2,T3 : TRANSFORMER
- It delivers signals fr om the telephone line
to modem or signals from modem to the
telephone
line.
- Insulation Detween prinary and
secondany circuit part.
Samsung Electronics 5-29
Circuit Description
5-5 SMPS (Switching Mode Power Supply)
5-5-1 AC Input Stage
AC Input power path is the Fuse(F201) for A C
current limit, the Varistor(TNR201) for by-passing
high voltage surge, the dischar ge r esistor(R201), the
AC Impulse Noise Filtering
C ircuit(C201/L201/C202), the Common Mode
Grounding Circuit(C203/C204), the 2’nd noise
filter(L202), and the thermistor(TH201). When
power is turned on, TH201 limits Power-On-InlushCurrent by it’s high resistance, and when it’s
temperature rise, it’s resistance become about zero
ohm.
5-5-2 SMC (Switched Mode Control)
The AC input voltage is rectified and filter ed by
DB201 and C207 to create the DC high voltage
applied to the primary winding of T201. T201 pin #1
is driven by the SMPS device TOP226(U201). U201
auto-starts and chops the DC voltage. The U201 is
PWM SMPS IC and has internally a SMC(switched
mode control) IC and a MOSFET output stage. The
SMC IC has a Auto-restart without a Power Supply
for the IC and a Thermal Shutdown function and so
on. C208/R208/D202 clamp leading- edge voltage
spikes caused by transformer leakage inductance.
The power secondary winding(pin #11-12) is
rectified and filter ed by D252,C251,L251, and C255,
C259 to create the 5V output voltage. The bias
winding(pin #4-5) is rectified and filter ed by D203
and C213 to create U201 bias voltage. The secondary
output 5V is regulated thr ough the path of the
voltage divide by R253/R254 - U251 switching PC252 - the bias voltage of U201 - U201 PWM duty
cycle - T201 secondary voltage. C209 filters internal
pin, determines the auto-restart fr equency, an d
together with R251 and R210, compensates the
control loop. Q251 of the secondary stage 24V is the
Low Power-loss Regulator with built-in over current
protection function and overheat protection
function, and consists a control IC and a drive
transistor. It switches the input DC voltage and the
switched DC voltage is filtered by C257. D204 and
D205 clamp impulse noises.
5-5-3 Fuser Drive
Fuser is drived by the Triac(Q201) that AC input
power is applied directly and the Phototriac(PC251) that is controlled by Engine contr oller.
The Thermistor resistance changes according to
Heat Roller in Fuser, the voltage in temperature
sensing circuit changes accor ding to this resistance
change, and this feedbacks to Engine Controller, it
controls temperature by PID method.
5-30 Samsung Electronics
Circuit Description
5-6 Engine Controller
5-6-1 Power On Reset
The reset cir cuit initializes the CPU(U3) at power on
and prevents unstable operation due to power
fluctuations. It consists of LM393(U5) - voltage
comparator- , and RC for reset timing.When a DC
3.8V or higher are applied to LM393’s pin #3, the ‘
RESET’ signal goes ‘HIGH’ and the CPU begins the
initialization pr ocedure, ‘RESET’ is active for
approximately 122ms.
5-6-2 CPU(+5V)
The used CPU is a 8bit micropr ocessor, SAMSUNG
KS88C4316(U3). This is operated at 6.944MHz and
controls all ICs. The shape is a 64pin DIP type.
5-6-3 EPROM (+5V)
The EPROM, 27C256(U2), has the storage capability
of 256KBits and the access time is 150ns. The
EPROM stores the pr ogram data that controls the
Engine part.
5-6-4 Address Latch
There contain Address and Data in CPU
port[1.7:1.0] signals. This signals ar e applied to
LS574(U4) and Addresses synchronize with
“AS”(Address Str obe) and output to EPROM(U2).
5-6-5 Extended Output Ports
HC259(U12) is composed of 3-to-8 Decoder and
Output Latch. Address x8000 to x8007 are mapped
Output Port, the D0 value is latched ports. This
outputs control the clutch, LSU, HVPS.
5-6-6 NVRAM Control
The NVRAM(U1) stores “Used Sheet Count” for
SET and Developer unit. To control it, it is selected
by “CS”, and “DI”/”DO” synchronizes with “SK”
clock writes in/r eads out the serial data to/fr om the
NVRAM.
5-6-7 Motor Driving(+24V)
The Motor Driver, SLA7029M(U207), is used to
drive the Main Stepping Motor. An
SLA7029M(U207) receives Motor Drive Enable and
two phase signals from the CPU. It then generates a
constant-current unipolar pulsed signal for Motor
driving, applied to the Motor through R5(1Ω, 5%,
3W) and R6(1Ω, 5%, 3W).
5-6-8 Solenoid Clutch(+24V)
The Solenoid controls the paper Pick-up Clutch. The
Solenoid receives contr ol signal fr o m U12 Q0.
KSC1008-Y(Q4) is the driving transistor, an d
1N4003(D1) protects KSC1008-Y(Q4) from the noise
pulse generated by deenergizing the Solenoid
5-6-9 Fuser Control(+24V, AC Power)
The Fuser Temperature Contro l circuit reads the
Heat Roller ’s Thermistor voltage at CPU port 5.0,
and turns the Fuser unit on and off via CPU port 6.4
and KSC1008 (Q3). If CPU port 6.4 or LM393(U5)
pin #7 are ‘LOW’, KSC1008 is off and the Fuser
Lamp is off. LM393’s pin #5 is pr oportional to fixing
unit’s temperature. LM393 pin #6 is the
‘OVERHEAT’ signal. If LM393 pin #5 is less than its
pin #6, its pin #7 output is ‘LOW’, keeping the
fixing unit of f. The ‘Fuser on’ signal of Q3 turns the
Triac thr ough the Photo LED on inside the Photo
Coupler(PC251). And PC151 trigger input signal
supplies into the Triac Thyristor(Q201), then the
Fuser ’s Heat Lamp turns on.
Samsung Electronics 5-31
Circuit Description
5-6-10 Cover Open Sensing(+24V)
“Cover Open Sensor” is placed on the left top of
Printer. If the front cover is open or Developer unit
is placed in, the Printer does not operate.
5-6-11 Paper Sensing(+5V)
There are three Sensors for the paper in the Printer:
1) Paper Empty Sensing
It is placed in Paper Cassette, and senses if there
ar e papers in Cassette.
2) Paper Feed Sensing
It is placed befor e Transfer process, and senses if
the paper is feeding. When the paper feeding is
sensed by it, Printer image data is output to LSU.
3) Paper Check
It is placed on the side of paper path. When
narrow paper(width is more than ???mm) is
feeding, the paper don’t touch the actuator, and it
is sensed the narrow paper. The Printer Engine
check resistance of Transfer Roller and the
feeding paper, i f the feeding paper width is
narro w, THV accor ding to the r esistance outputs
higher voltage than wide paper.
4) Exit Sensing
It is placed in the exit of Printer, and senses the
paper exit.
5-6-12 LSU Control
LSU is composed of a polygon mirror motor and a
laser gun part. The polygon mirror motor starts
r otation by ‘PMOTOR” signal and r eaches the
constant speed, “LREADY” signal outputs “High”
from LSU. And when video image signal fro m
V ideo Controller is applied to Laser Gun, it fir e the
laser beam. And the polygon mirro r r eflects and
scans the beam horizontally. When the scanned laser
beam reaches at the side of LSU, “HSYNC” outputs
one pulse. Video controller synchronizes this signal,
and outputs the left edge of image.
5-6-13 Toner Check
Toner sensor is placed in the rear of Developer unit
to check the toner supply. During warming up and
printing, the controller checks the output signal of
toner sensor. I f toner is suf ficient, the output signal
of †oner sensor is High, and if not, the output signal
is Low. When the output signal of toner sensor
r emains low for more than 5 seconds, controller
judges. Toner is insufficient, and displays ‘Toner
low’. In toner low condition, the printer prints
approximately 300 sheets. Then the controller
displays ‘Toner Empty.’
5-32 Samsung Electronics
Circuit Description
5-7 H.V.P.S. (High Voltage Power Supply)
5-7-1 Output Specifications
5-7-2 Transfer High Voltage(THV)
THV output is a series circuit of positive and negative voltage generation part. Negative output is for cleaning
the OPC Dru m and positive output is for drawing the Toner on the paper. High voltage is generated by DCDC Converter that is composed of a PWM Contro l C i rcuit, a Blocking Oscillator and 4 times voltage rectifying
cir cuit. the “THV-EA” goes to “low” positive and negative parts operate. And this state, THV positive output is
controlled by “THV-PWM” duty cycle, when it goes to “High”, positive part outputs 0V, and negative part only
output -1000V. When some duty cycle is applied to the PWM input of H.V. circuit, THV terminal outputs
positive voltage.
5-7-3 Main and Bias High Voltage(MHV,SUPPLY,DEV)
MHV generation part is composed of blocking oscillator and double voltage rectifying cir cuit. When “MHVEA” signal goes to “High”, the MHV outputs, and this state, when “SUPPLY-EA” or “DEV-EA” input goes to
“Low”, SUPPLY or DEV terminal corresponding it outputs the voltage that is generated by dropping MHV.
DEV output voltage is selectable 300V or 350V.
Item Printing/Initial DCU On
Supply Voltage -500V -500V
Bias Voltage -300V -300V
THV(Transfer High Voltage) (-) -1KV -1KV
THV(Transfer High Voltage) (+)
MHV(Main High Voltage) -1.4KV -1.4KV
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