EPSON Stylus COLOR 900/900N
Chapter 3 Troubleshooting
85
Table 3-32. Cleaning Does Not Solve the Print Problem (continued)
Table 3-33. Cleaning Does Not Solve the Print Problem (continued)
Step
Problem
Solution
8
Is a head driver
transistor defective?
Locate the following four power transistors attached to
the heatsink on the main board:
• Q3 and Q4: Output the common voltage for rows
A and B (black nozzle rows).
• Q5 and Q6: Output the common voltage for rows
C, D, and E (color nozzles).
To check if each pair of transistors is working
properly, check the trapezoidal waveform at the
emitter terminal of the charging transistor (Q3 and
Q5). Perform the check while printing.
NOTE: The frequency and amplitude of the
waveform vary while printing. As long as the
trapezoidal waveform is output, the head
driver transistors are considered good.
D 2 0 8 2
B 1 3 8 2
D 2 0 8 2
B 1 3 8 2
T H
H e a t S i n k
Q 4
Q 3
Q 6
Q 5
T r f o r t h e
b l a c k n o z z l e s
T r f o r t h e
c o l o r n o z z l e s
B
E
+
2 0 V
2
µ
+
Step
Problem
Solution
9
Is the printhead pre-
driver IC defective?
Check for the waveform at the base of transistors
Q3 - Q6 as shown below.
If the waveform is not output correctly from Q3 or
Q4, replace IC15 on the main board; if it’s not
output correctly from Q5 or Q6, replace IC16. If the
waveform is output correctly, replace the
corresponding power transistor.
T H
H e a t S i n k
Q 4
Q 3
Q 6
Q 5
D 2 0 8 2
B 1 3 8 2
D 2 0 8 2
B 1 3 8 2
B
E
T r f o r t h e
b l a c k n o z z l e s
T r f o r t h e
c o l o r n o z z l e s
2 0 V
2
µ
Summary of Contents for 900N
Page 1: ...EPSONStylusCOLOR900 900N Color ink jet printer TM SC900 N 6 59 0 18 ...
Page 8: ... 37 5 PRODUCTDESCRIPTION ...
Page 37: ... 37 5 OPERATINGPRINCIPLES ...
Page 67: ... 37 5 TROUBLESHOOTING ...
Page 89: ... 37 5 DISASSEMBLYANDASSEMBLY ...
Page 121: ... 37 5 ADJUSTMENTS ...
Page 156: ... 37 5 MAINTENANCE ...
Page 169: ... 37 5 APPENDIX ...
Page 179: ...EPSON Stylus COLOR 900 900N Chapter 7 Appendix 176 Figure 7 3 C265 Main Board Soldering side ...
Page 181: ...EPSON Stylus COLOR 900 900N Chapter 7 Appendix 178 Figure 7 6 C265 PNL Board ...
Page 195: ...06 03 01 02 for S E ASIA 03 03 05 03 04 EPSON STYLUS COLOR 900 No 7 10056 Rev 01 ...
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