Epson Stylus Color 740 Service Manual

EPSON Stylus COLOR 440, 640, and 740 Chapter 3 Troubleshooting
78
Table 3-6. Unit Repair of Main Board
Symptoms Condition Cause Check Point Solution
The printer does not
operate at all.
(Continued on the next
page.)
CPU does not operate.
(Continued on the next
page.)
The reset circuit does not
operate.
Stylus COLOR 440, 640:
Check the waveform of the
+5V and /Reset signal of
IC9.
Pin 7 = +5 volts
Pin 6 = /Reset
Replace IC9.
Stylus COLOR 740:
Check the waveform of the
+5V and /Reset signal at
IC8.
Pin 7 = +5 volts
Pin 2 = /Reset
Replace IC8.
Control ROM, D-RAM,
and Mask ROM are
defective, or are not
being selected
correctly.
(Continued on the next
page.)
Stylus COLOR 440:
If you cannot find a waveform at the following pins, their
respective ICs are defective:
Pin 88 of IC1
Pin 20 of IC3
Pin 26 of IC4
Stylus COLOR 440:
Replace IC1, IC3, or IC4.
Stylus COLOR 640:
If you cannot find a waveform at the following pins, their
respective ICs are defective:
Pin 97 of IC1
Pin 13 of IC3
Pins 98 and 99 of IC1
Pin 27 of IC5
Pin 14 of IC6
Stylus COLOR 640:
Replace IC1, IC3, IC5, or IC6

Epson Stylus Color 740 Specifications

General

Brand	Epson
Model	Stylus Color 740
Category	Printer
Language	English