Checking Motors And Sensors; Troubleshooting Print Quality Problems - Epson Stylus Photo 870 Service Manual

EPSON Stylus Photo 870/1270

3.4 Checking Motors and Sensors

Table 3-8. Motor Resistance Measurement Procedures
Motor Name Location
Carriage motor CN14 (main board)
Paper feed motor CN13 (main board)
ASF/Pump motor CN7 (main board)
If all the motors check out okay and the connectors are secure, the problem is most
likely caused by a faulty driver on the main board.
Table 3-9. Sensor Check Measurement Procedures
Sensor name Location
Paper end sensor CN5 Pins 1 and 2
Positive on 1
Negative on 2
ASF home position CN6 Pins 1 and 2
sensor
Positive on 1
Negative on 2
Note:The power supply (pin 3) for the PE and ASF sensors is 5 V with the sensor
disconnected and about 1.1 V with the sensor connected.
Checkpoint Setting
Ω
Pins 1 and 2 29.2 +/– 25%
Ω
Pins 1 and 2 29.2 +/– 25%
Ω
Pins 1 and 3 10.28 +/–10%
Pins 2 and 4
Voltage Indication
Detects paper: When you actuate the
LOW (0.1 V) sensor, the voltage
should toggle between
No paper: HIGH
HIGH and LOW.
(5.0 V)
Detects the ASF When you actuate the
home position: sensor, the voltage
LOW (0.1 V) should toggle between
HIGH and LOW.
ASF home
position not
detected:
HIGH (5.0 V)

3.5 Troubleshooting Print Quality Problems

If you notice that print quality declines, it is usually because:
! The printhead nozzles are clogged.
If printouts are missing dots or contain horizontal white lines
(banding), clean the printhead as described in
Printhead" on page 85. If cleaning doesn't solve the problem, see
Table 3-11 for other possible solutions.
! The bidirectional adjustment setting is incorrect.
If printouts contain misaligned vertical lines, align the printhead as
described in "Bi-Directional Alignment"
NOTE: Follow each step in the order given, performing the
action described in the "Action" column using the
instructions in the "Instructions" column.
Chapter 3 Troubleshooting
"Cleaning the
on page 88.
34