EPSON Stylus Photo 750 Revision A

Troubleshooting Overview 39

3.1 Overview

This section describes how to identify and troubleshoot the problems

when repairing the printer by dividing the troubles into two levels; repair

and replacement of the assemblies and units, and repair of the

components. Refer to the flowchart below and perform repairing the

component after separating the defective units.

Figure 3-1. Troubleshooting Flowchart

Table 3-1. Motor, Coil Resistance

Table 3-2. Sensor Check Point

Motor Location Check Point Resistance
CR Motor CN7 Pin 1 and 3
Pin 2 and 4
7.8 Ohms ± 10% (at
25 °C/one phase)
PF Motor CN8 Pin 1 and 3
Pin 2 and 4
8.8 Ohms ±10%
(at 25 °C/one phase)
START
END
Unit Level Troubleshooting
Unit Repair
(P S B /P S E )
Unit Repair
(Main board)
Disassemble and Adjustment
Unit Repair
(P rinte r M ec ha n ism )
Sensor Name Check Point Signal Level Switch Mode
HP Sensor CN4/Pin 1 and 2
Less than 0.7V Open (Out of HP
range)
More than 2.4V Close (Within H P
range)
PE Sensor CN5/Pin 1 and 2 Less than 0.7V Open (Paper
exists)
More than 2.4V Close (No paper)
ASF Sensor CN6/ Pin 1 and 2
Less than 0.7V Open (Paper Feed
Roller home
position)
More than 2.4V Close (Out of home
position)
Thermistor
(THM)
Head side CN9/
Pin 3 and 4 Analog signal 10 K (at 24 °C)
Black cartridge
sensor (COB) Head side CN9/
Pin 1 and 4
Open (Cartridge is installed)
Close (No Cartridge)
Color cartridge
sensor (COC) Head side CN9/
Pin 2 and 4
Open (Cartridge is installed)
Close (No Cartridge)