Epson DFX-8500 Service Manual page 187

5.2 CIRCUIT BOARD REPAIR
This section provides detailed troubleshooting methods to isolate components in the power supply or on the
main board. This information is for use by service personnel who repair to the component level.
The table below provides causes, checkpoints, and solutions for different power supply circuit problems. The
checkpoints include waveforms for normal operation. By referring to the checkpoints, determine the defective
component. Then perform the proper repair. The table provides the following four columns:
‰Symptom:
Check this column for a list of common printer problems.
‰Cause:
Use this column to identify possible causes that could produce this symptom.
‰Checkpoint:
Follow the troubleshooting checks in this column to isolate your problem.<
‰Solution:
Repair the printer using the instructions in this column.
5.2.1 C204 PSB/PSE Board Repair
Table 5-4 indicates majour components which is used for the C204 PSB/PSE board and Table 5-4 shows the
C204 PSB/PSE board component level troubleshooting.
Location
DB1
TY1
QF101
QF201
IC101
IC204
Symptom
No DC voltage is present
at the output . (Fan on
the power supply board
doesn't rotate at all.)
Fuse F1 blows
immediately after
replacement.
Rev. B
Table 5-4. C204 PSB/PSE Board Main Parts List
Table 5-5. C204 PSB/PSE Board Component Repair 1/3
Cause
PD signal is HIGH (sent
from the main board).
The DRERR signal is
HIGH.
CL signal is HIGH.
The line filter circuit is
defective.
Description
Diode bridge
TRIAC
Switching FET for VP1 and VP2
Switching FET for VP3 and +5 VDC
PWM switching controller
+5 V regulator IC
Checkpoint
Measure the signal level
of the PD signal at CN4.
Measure the signal level
of the DRERR signal at
CN4.
Measure the signal level
of the CL signal at CN4.
Check if any of pins
C1-C5 or R1 is shorting
the AC line.
TROUBLESHOOTING
Solution
Wait until the printer
prints again.
Replace the E05B36 on
the C204 MAIN board.
Replace the printhead
driver on the C204 MAIN
board and/or C204 DRV-
B board.
Wait until the printer
prints again.
Replace the E05B36 on
the C204 MAIN board.
Replace the abnormal
element.
5-13