Checking For Power Supply Problems - Epson Stylus COLOR 900 Service Manual

EPSON Stylus COLOR 900/900N

3.1.2 Checking for Power Supply Problems

Check for problems in the order listed below if the printer does not come
on after you plug it in and press the power button (the printer does not
perform initialization and no LED indicators come on). You can also use
the steps below to diagnose intermittent power problems that occur
during operation.
NOTE: If you answer "Yes" to a question listed under "Problem," take
the action described to the right under "Solution." If "No,"
proceed to the next step.
W A R N I N G
The external power switch is only a secondary switch
in the power supply circuit. The primary side of the
power supply is always "hot," even when the printer
appears to be off. Always unplug the printer before
servicing.
Table 3-16. Isolating the Problem on the Power Supply Board
Step Problem
1 Are any connections Check the following connections:
between the control
• the control panel FFC's connection to the control
panel and the power
supply disconnected?
• the control panel FFC's connection to the relay
• connector CN15 on the main board
2 Has the fuse (F1) on Check fuse F1 located beside connector CN1 on
the power supply board the power supply board.
blown?
3 Is CN2 or CN3 on the Check that connectors CN2 and CN3, which supply
power supply board power to the main board, are properly connected.
disconnected?
Solution
panel
board (black, 12-pin)
Table 3-17.
Isolating the Problem on the Power Supply Board (continued)
Step Problem
4 Is CN 5 or CN6 on the Check that connectors CN5 and CN6, which
main board receive power from the power supply board, are
disconnected? properly connected.
5 Is the choke coil Turn the power supply board upside down and
broken? check for continuity at the two points indicated in
the figure below.
6 Is the transformer (T1) Referring to the figure below, check for an open coil
broken? in the transformer between pins 3 and 4, and
between pins 11 and 14.
Chapter 3 Troubleshooting
Solution
76