EPSON Stylus Color 900 Revision C
Troubleshooting Overview 97
Table 3-31. Cleaning does not Solve the Print Problem (continued) Table 3-32. Cleaning does not Solve the Print Problem (continued)
Step Check Point Action
6 Is any ink tube
disconnected from
the cap unit?
Referring to the figure below, check the following
points:
• Connection between two tubes and the bottom of
the cap (Remove the whole cap from the unit to
check the connection.)
• Connection of each tube and the separator.
• Connection of one tube at the bottom of the valve
7 Is the FFC
disconnected from
the printhead
board?
Remove the printhead unit from the carriage unit, and
bring the printhead surface side upward to check that
two FFC is properly connected. Even though no slant
connection nor disconnection is found, disconnect
the FFC once and install them again.
Applying/releasing
the m inus pressure
Left tube
(se m itra nsp a ren t)
Ink absorption
Right tube
(w hite )
CW
CCW
Separator
FFC 2
FFC 1
Step Check Point Action
8 Is the head driver
transistor defective?
If you see the C265 Main board from the heat sink
side, the following four power transistors can be
found:
• Q3 and Q4: Outputs the common voltage for the
row A and B (black nozzle rows)
• Q5 and Q6: Outputs the common voltage for the
row C, D, and E (color nozzles)
To check if each pair transistor is working properly,
check the trapezoid waveform at the emittor terminal
of the charging side (Q3 and Q5). Check the
waveform while running a print.
NOTE:
Frequency of waveform and voltage level
(p-p) varies if printing is performed through
the driver. Therefore, as long as the
trapezoid waveform is output, the head
driver IC is considered good, and the
printhead must be replaced in that case.
D2082B1382D2082B1382
TH
Heat Sink
Q4
Q3
Q6
Q5
Tr for the
black nozzles
Tr for the
color nozzles
B
E
+
20V
2
µ
+
