DOWNLOAD Panasonic KX-MB283RU / KX-MB783RU Service Manual ↓ Size: 15.15 MB | Pages: 127 in PDF or view online for FREE

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The general ITS operation is performed by IC200 which has a handset circuit. The alarm tone, the key tone, and the beep are
output from Soc IC300.

1. Function

This is the function when you are not holding the handset and can hear the caller’s voice from the line.

2. Circuit Operation

(Telephone Monitor Signal Path)
Signals received from the telephone line are output through at the speaker via the following path.

3. Signal Path

TEL LINE

→D103→Q104→C106→IC101(3-5,6)→IC100(9,10-5)→IC300(AD26-AB24)→IC200(4-1)→IC202(2-1)→IC204(4-

5,8)

→CN200(1,2)→CN58(1,2)→CN57(1,2)→SPEAKER

1. Function

This circuit monitors various tones, such as (1) DTMF tone, (2) Alarm/Beep/Key tone/Bell.

2. Signal Path

a. DTMF MONITOR

(Speaker Operation)
IC300(AB24)

→IC200(4-1)→IC202(2-1)→IC204(4-5,8)→CN200(1,2)→CN58(1,2)→CN57(1,2)→SPEAKER

(Handset Operation)
IC300(AB24)

→IC200(4-16)→IC203(4-8)→CN200(7,8)→CN58(7,8)→OPTION  HANDSET UNIT

b. ALARM/BEEP/KEY TONE/BELL

IC300(B20)

→IC202(2-1)→IC204(4-5,8)→CN200(1,2)→CN58(1,2)→CN57(1,2)→SPEAKER

1. Function

When TAM is connected to this unit, the unit receives documents for FAX calls or the external TAM records a voice message
automatically.

2. Circuit Operation

The TAM INTERFACE circuit consists of Soc(IC300) to detect the other party CNG signal, and RLY100 to separate EXT.TAM.

a. CNG signal detection circuit

The CNG signal from the other party’s FAX is detected in Soc IC300 
(Signal path)
TEL LINE

→IC101 (8,9 - 5,6)→IC100 (9,10 - 5)→IC300(AD26)

b. Remote receiving

This is the parallel-connected DTMF signal for the TEL or EXT.TEL mode between T and R. When the other party is a
FAX, the unit switches to FAX receiving.
(Signal Path)
TEL LINE

→IC101 (8,9 - 5,6)→IC100 (9,10 - 5)→IC300(AD26)

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The scanning block of this device consists of a control circuit and a CIS (contact image sensor), and AFE (Analog Front End)
include A/D Converter.

When an original document is inserted and the start button pressed, pin A3 of IC300 goes to a low level and the transistor Q518
turns on. This applies voltage to the CIS. The CIS is driven by each of  the CCDSH , CCDCLK  signals output from IC300, and the
original image illuminated by the LED to output an analog image signal. 
The analog image signal is input to the AFE on VINP(20pin of IC503) and converted into 16-bit data by the A/D converter inside
IC503. Then this signal undergoes digital processing in order to obtain a high-quality image.

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1. Functions

All driving forces of printer engine part are supplied by this engine motor.
Engine motor is controlled so as to rotate at constant speed during printing and copying.

2. Motor operation

<Start operation>
In order to start the motor rotation, following 3 signals are supplied from IC300.
1. SS signal (Output pin: Pin B12/Output Signal: "H")
When this signal is inverted by transistor Q502 and becomes "L", motor recognize this signal as "start" signal.
2. Clock signal (Output pin: Pin A12/Output Signal: Pulse)
Pulse frequency :approx. 1.9KHz (at normal printing speed, )
Pulse frequency :approx. 0.5KHz.(at half printing speed)
This signal is also inverted by transistor Q525, and supplied to motor as "clock" signal .
3. Brake signal (Output pin: Pin C12/Output Signal: "H")
When this signal is inverted by transistor Q526 and becomes "L", motor recognize this signal as "brake off" signal.

When motor reaches constant speed, "L" signal is supplied from motor to IC300 pin B12 as "Lock detect (LD)" signal.
if "LD" signal does not becomes "L" within predetermined period after "SS" signal becomes "H",  or if "LD" signal becomes
"H" during rotation, it is judged that motor Error occurred.

Timing Chart of Start operation

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<Stop operation>
In order to stop the motor rotation, following 2 signals are supplied from IC300.
1. SS signal (Output pin: Pin B12/Output Signal: "L")
When this signal is inverted by transistor Q502 and becomes "H", motor recognize this signal as "stop" signal.
2. Brake signal (Output pin: Pin C12/Output Signal: "L")
When this signal is inverted by transistor Q526 and becomes "H", motor recognize this signal as "brake on" signal.

Timing Chart of Stop operation