Oki OKIFAX 5750 Maintenance Manual page 781

3.1.3 Read image data NG
3: Read image data NG
Sensor LED is not lit
Yes
Pin 2 of TR506 becomes
"H" when the sensor is lit.
Yes
Voltage of pin 3 of TR1
comes down about 0.7V or
more than pin 1 when
the sensor is lit.
Yes
Pin 2 of TR1 becomes 5V
when the sensor is lit.
Yes
Pin 3 and 5 of IC15
are about 0.4V.
Yes
Pin 1 of TR12 and Pin 1
of TR13 are about 0.4V.
Yes
Check CN13
41285901TH Rev.3
No
No
Replace IC2
No
Replace TR506
No
Replace TR1
peak of pin 39 is between
No
Replace D10
No
Replace IC15
or TR12, TR13
Pin 2 of TR505 becomes
"H" when the sensor is lit.
Yes
Voltage of pin 3 of TR2
comes down about 0.7V
or more than pin 1 when
the sensor is lit.
Yes
Pin 2 of TR2 becomes 5V
when the sensor is lit.
Yes
Waveform of pins 39, 61,
63 of IC26 are similar to
Figure 3.1-6 or waveform
0.8V and 4.0V.
Yes
Waveform of pin 3 of IC14
is similar to Figure 3.1-7 or
waveform peak of output is
between 0.2V and 1.0V.
Pin 42 of IC26 is
about 4.0V
Pin 38 and 44 of IC26 are
about 1.8V
Pin 37 of IC26 is
about 0.8V
Yes
Replace IC26
or Replace IC2
No
Replace IC2
No
Replace TR505
No
Replace TR2
No
No
Yes
Yes
Replace IC14 Check CN13
Replace TR14,
No
D8 or Check
the peripheral
resistor value
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