Epson DLQ-3000 Service Manual page 155

DLQ-3000+
Condition
T T
Symptom : Abnormal printing
Printhead Printhead control
control circuit circuit is
operates defective.
abnormally.
Printhead driver
circuit is
defective.
PG motor is not PG motor driver
functioning circuit is
properly. defective.
Note:
1. HD -No. shown in the diagram and corresponding dot No. are the same.
5-16
Table 5-13. Repair of C210 MAIN Board (continued)
Cause
If some particular dots are missing or
bad, check which head driver is
causing the problem, the driver for
print pulse A or B.
If any of the drivers is bad, see the
circuit diagram and replace the
corresponding drive transistors (Q6
to Q33, QM3 to QM10). (See Note 1.)
If both drivers are good, gate array
IC25 is defective.
Figure 5-14. Head Drive Signal Waveform
Check pin 3 of 3-terminal regulator
IC17 for the correct output voltage (+12
V). If it's correct, gate array IC25 is
defective.
Check pins 1,3,5,and 7 of QM1 for the
input signal waveform and pins
15/16, 13/14, 11/12 and 9/10 of QM1
for output signal waveform.
If no motor phase input signals is
input, gate array IC25 is defective.
If no drive waveforms is output, QM1
is defective.
Check point
Figure 5-15. PG Motor Drive waveform
Solution
Replace the
main control
board or
associated
component.
Replace the
main control
board or any
associated part.
Replace the
main control
board or any
associated
parts.
Rev. A