Panasonic KX-FT21BX Service Manual page 158

KX-FT21LA
[Read Position Sensor (PS2) ]
When a document is brought to the read position, the shelter plate passes the sensor light, the phototransistor becomes ON,
and the input signal of the CN2-3 pin (Operation) becomes a low level. When there is no document at the read position, the
shelter plate closes the sensor light, the phototransistor becomes OFF, and the input signal of the CN2-3 pin (Operation)
becomes a high level. (When checking this sensor, CN1-8 pin, 2pin becomes low level).
+5V
CN1-8pin
Q3
R10
D1
R11
Q2
[Document Sensor (PS1) ]
When a document is set, the shelter plate closes the sensor light, the phototransistor becomes OFF, and the input signal
of the CN2-3 pin (Operation) becomes a high level. When there is no document, the shelter plate passes the sensor light,
the phototransistor becomes ON, and the input signal of the CN2-3 pin (Operation) becomes a low level.
(When checking this sensor, the CN1-8 pin, 3pin becomes a low level.)
+5V
CN1-8pin
Q3
R10
D1
R11
Q1
SHELTER PLATE
+5V1
R12
CN2-3pin
Out of the Read Position
At the Read Position
CN1-2pin
SHELTER PLATE
+5V1
R12
CN2-3pin
CN1-3pin
- 132 -
Operation Board
Phototransistor
Operation Board
Phototransistor
No document ON
Set document OFF
Signal (CN2-3 Pin)
OFF High level
ON Low level
Signal (CN2-3 Pin)
Low level
High level