Epson Stylus Color 740 Service Manual

EPSON Stylus COLOR 440, 640, and 740 Chapter 3 Troubleshooting
75
Table 3-5. Repair of the C206/C257 PSB/PSE Board
Symptom Condition Cause Checkpoint Solution
The printer does
not operate at all.
+42 V line is dead. F1 is open. Check F1 with a multimeter. Replace F1.
Transformer coils are open. Check for a waveform
across the drain and
source of Q1. If the
transformer is open, no
voltage (no waveform)
should be present.
Replace T1.
Switching FET (Q1) is
defective.
Check at the drain. If the
FET is open, the
waveform will be a flat,
positive voltage.
Replace Q1.
Feedback transistors (Q2,
Q3) are defective.
Check at the collector. Replace Q2 or Q3.
+42 V line is abnormal. Check the following parts.
• ZD87, ZD52
• ZD51, ZD81–ZD86
•PC1
Replace
malfunctioning
parts.

Epson Stylus Color 740 Specifications

General

Brand	Epson
Model	Stylus Color 740
Category	Printer
Language	English