Panasonic KX-MB283RU / KX-MB783RU Service Manual ▷ View online
53
KX-MB283RU/KX-MB783RU
6.14. LCD SECTION
The Gate Array (IC1) works only for writing the ASCII code from the data bus (D4~D7). V0 is supplied for the LCD drive.
R118 and R117 are density control resistors.
Consequently, in this unit, the timing (positive clock) is generated by the LCD interface circuitry in the gate array (IC1).
R118 and R117 are density control resistors.
Consequently, in this unit, the timing (positive clock) is generated by the LCD interface circuitry in the gate array (IC1).
54
KX-MB283RU/KX-MB783RU
6.15. HVPS (High Voltage Power Supply) SECTION
6.15.1. HVPS SPECIFICATION
As for the developing voltage, the DC voltage and AC voltage are overlapped and output from an output terminal.
There is one terminal for transcription output and + and - are switched to be output.
There is one terminal for transcription output and + and - are switched to be output.
6.15.2. CHG-BIAS (Charge BIAS)/GRID/ UNIT
When IC300 turns on the transistor Q506, CHG REM becomes “L”, and Charge BIAS (200
µA) is output from CHG OUTPUT.
GRID BIAS is generated by the current flowing in the GRID circuit via charge wire and GRID.
Charge (CHG)
Grid
Developing DC
Developing AC
Transfer (TRA) -
Transfer (TRA) +
Output Characteristics Constant current
Constant voltage
Constant voltage
Constant voltage
Constant current
(Variable)
(Variable)
Constant voltage
Nominal Output Voltage 4.35KV
475±10V
230V±15V
(50~300V)
PWM20%
300M
(50~300V)
PWM20%
300M
Ω/220pF
330V±15Vp-p
34KHz
34KHz
100M
Ω
(-1.48KV)
785V±100V
Nominal Output Current 200±15
µA
(19.4M
Ω)
200
µA
0.73
µA
-----
-14.8
µA±1µA
(0
µA~25µA)
PWM 35%
1000M
Ω
(0.8
µA)
Load Range
18.1M
Ω~20.6MΩ
-----
100M
Ω~2000MΩ
-----
33.8M
Ω~284MΩ
10M
Ω~1000MΩ
Constant Current
Range
Range
4.1~4.6KV
-----
-----
-----
-0.5KV ~ -4.2KV
-----
55
KX-MB283RU/KX-MB783RU
6.15.3. DEV DC BIAS UNIT
When CHG REM is “L”, 5.425kHz PWM (Pulse Width Modulation) is input from IC300 to DEV CLK through Q504, developing
voltage corresponding to the DUTY of PWM signal is output from DEV OUTPUT. Also DUTY is adjusted by the utilization of the
developing unit and environmental temperature.
voltage corresponding to the DUTY of PWM signal is output from DEV OUTPUT. Also DUTY is adjusted by the utilization of the
developing unit and environmental temperature.
6.15.4. DEV AC BIAS UNIT
330 Vp-p 34 kHz wave of developing AC voltage is output from DEV OUTPUT. This voltage is overlapped with developing DC
voltage and output as AC voltage that includes the development DC voltage.
voltage and output as AC voltage that includes the development DC voltage.
6.15.5. TRA (+) BIAS (Transfer (+) BIAS)/TRA (-) BIAS (Transfer (-) BIAS) UNIT
When CHG REM is “L” and TRA CLK is “open”, Charge BIAS (200
µA) is output from CHG OUTPUT, and at the same time
Transfer (+) BIAS (785V) is output from TRA OUTPUT. When 5.086kHz PWM (Pulse Width Modulation) signal is input to TRA
CLK through transistor Q501, Transfer (-) CURRENT BIAS corresponding to PWM signal is output from TRA OUTPUT.
CLK through transistor Q501, Transfer (-) CURRENT BIAS corresponding to PWM signal is output from TRA OUTPUT.
56
KX-MB283RU/KX-MB783RU
6.16. HEAT LAMP CONTROL CIRCUIT
The temperature of the fixing part of the Fuser Unit is converted to a voltage by THERMISTOR and input to IC300-D19pin. The
heat lamp is turned on/off by the HTRCTL signal (IC300-AD19pin) through the photo triac (PC2) and the triac (SCR51). And two
thermostats are set on the AC line as the safety devices.
heat lamp is turned on/off by the HTRCTL signal (IC300-AD19pin) through the photo triac (PC2) and the triac (SCR51). And two
thermostats are set on the AC line as the safety devices.
1. Control at Printing
a. After the printing signal is received, turn ON the heater.
b. After that, turn ON the motor at the Primary Stable Temperature (170
b. After that, turn ON the motor at the Primary Stable Temperature (170
°C).
c. After that, control at the Secondary Stable temperature (195
°C/200°C), and feed papers.
Click on the first or last page to see other KX-MB283RU / KX-MB783RU service manuals if exist.