LQ-670 Service Manual
Rev. A
5-15
Symptom
Condition
Cause
Checkpoint
Solution
Printer goes to
error state.
Fatal error.
+42V monitor
circuit is defective.
Check the voltage of 3 or 4
pin in CN3.
•
If the voltage is normal,
CPU is defective.
Replace the main
board or power
supply circuit board.
Carriage control
circuit is defective.
Check the output signal of
pin 1, 8,11,18 and input
signal of pin 5, 6,16,17 of
IC3.
•
If the phase signal of the
motor is not input, gate
array IC25 is defective.
•
If the drive waveform is
not output, IC7 is defective.
Pin 1 of IC3
Pin 5 of IC3
Figure 5-13. Waveform of
the Carriage Motor Drive
Replace the main
board or IC3.
Abnormal
printing
Print head
control is
abnormal.
Print head control
circuit is defective.
Measure the base voltage
of Q1
∼
Q24 and collector
voltage.
•
When the input signal is
not detected on the base
side, gate array is
defective.
•
If the output waveform is
not detected in the
collector, driver transistor is
defective.
Base
Collector
Figure 5-14. Head Drive
Signal
Replace the main
board or
corresponding
transistor.
Table 5-12. Repairing C214 Main Board (Con.)
Summary of Contents for LQ 670 - B/W Dot-matrix Printer
Page 1: ...EPSON IMPACT DOT MATRIX PRINTER EPSON LQ 670 SERVICE MANUAL SEIKO EPSON CORPORATION 4007875 ...
Page 5: ...v REVISION SHEET Revision Issued Data Contents Rev A May 28 1997 First issue ...
Page 114: ...Chapter 6 Maintenance 6 1 Preventive Maintenance 6 1 ...
Page 116: ...LQ 670 Service Manual Rev A 6 2 Figure 6 1 Lubrication Points ...
Page 122: ...LQ 670 Service Manual Rev A A 5 A 2 Circuit Diagram Figure A 2 C214Main Board Circuit Diagram ...
Page 123: ...Appendix Rev A A 6 Heat Sink Q1 D51 Figure A 3 C214PSB Board Circuit Diagram ...
Page 124: ...LQ 670 Service Manual Rev A A 7 Heat Sink Q1 D51 Figure A 4 C214PSE Board Circuit Diagram ...
Page 125: ...Appendix Rev A A 8 A 3 Component Layout Figure A 5 C214 Main Board Component Layout ...
Page 127: ...Appendix Rev A A 10 A 4 Exploded Diagram Figure A 8 Exploded Diagram ...
Page 128: ...LQ 670 Service Manual Rev A A 11 Figure A 9 Exploded Diagram ...
Page 129: ...Appendix Rev A A 12 Figure A 10 Exploded Diagram ...
Page 135: ...EPSON SEIKO EPSON CORPORATION ...