Epson Stylus PHOTO 890 Service Manual page 76

EPSON Stylus Photo 890/1280/1290
Table 3-15. Cleaning Does not Solve the Problem (continued)
Step Checkpoint Action
7 Check if the head FFCs Remove the head FFC holder from the CR unit, and
have come off the check that both FFCs are properly connected. Even if
printhead. they appear to be properly connected (not slant), try
disconnecting and then connecting them.
8 Check if the head The common driver transistors Q2 and Q3 are attached
driver is defective. the heat sink on the main board. To check their
conditions, check the sawtooth waveform at the emitter
terminals the transistors using an oscilloscope.
TROUBLESHOOTING
Head FFCs
Head Board
Table 3-15. Cleaning Does not Solve the Problem (continued)
Step Checkpoint
9 Check if the pre-driver
IC (IC10 or IC11) is
defective.
Overview
Action
If the waveform is not output in the previous step, check
for the waveform at the base of Q2 and Q3. Check for
the sawtooth waveform output from the pre-driver IC.
• If the correct waveform is output, transistor Q2/Q3 is
defective.
• If the correct waveform is not output, the pre-driver
IC is defective.
Revision C
76