Service manual

EPSON Stylus Photo 870/1270 Revision B
TROUBLESHOOTING Overview 67
3.1.2 Isolating the Faulty Part on the Power Supply Board
This section explains how to troubleshoot the following problems:
!
The printer is turned on but it does not perform initialization and
no LED indicators come on.
!
Problems occurs after the printer is turned on.
Be sure to troubleshoot in the order specified since the steps are listed in
the disassembly order to facilitate the job.
NOTE:
If you answer “Yes” to a question listed under “Checkpoint”, take the
action described to the right under “Action”. If “No”, proceed to the
next step.
Table 3-10. Isolating the Faulty Part on the Power Supply Board
Step Checkpoint Action
1 Is the Panel FFC
disconnected from
the connector on the
panel board?
The power switch for this printer is in the
secondary side. Therefore, if the FFC does not
transmit signals, the power supply board is not
active despite the main board operates
properly.
2 Is the Panel FFC
disconnected from
CN11 (black, 12-pin)
on the Main Board?
The power switch for this printer is in the
secondary side. Therefore, if the FFC does not
transmit signals, the power supply board is not
active despite the main board operates
properly.
3 Has the Pin 3 of the
panel FFC broken?
Check for the Pin 3 using a circuit tester.
4 Has the fuse (F1) on
the power supply
board blown out?
Check if the F1 located beside CN1 on the power
supply board has blown out.
5 Is CN1 on the power
supply board
disconnected?
Check if CN1 is properly connected. CN1
supplies AC power to the primary side of the
power supply board.
6 Is CN10 on the main
board disconnected?
Check if CN10 on the main board is properly
connected. CN10 supplies DC voltage to the
control circuit.
7 Is the choke coil L1
broken?
Turn the power supply board up side down and
check for the electrical continuity at the two
points below:
8 Is the transformer
(T1) broken?
Referring to the figure below, check if the
transformer is disconnected from the pole. Try
every combination.
Table 3-10. Isolating the Faulty Part on the Power Supply Board
Step Checkpoint Action
L1 (reverse side)
tr16
L1 (reverse side)
tr17