Epson 2070 Service Manual - Page 137

Cause, Solution, LQ-2070 Service Manual, Troubleshooting, Problem, Rev.A

Get Epson 2070 - LQ B/W Dot-matrix Printer PDF manuals and user guides
UPC - 010343812277
View all Epson 2070 manuals
Add to My Manuals
Save this manual to your list of manuals

Page 137 highlights

LQ-2070 Service Manual Troubleshooting Table 5-7. Repairing the C186 MAIN Board Assembly Problem Cause IC1 is defective. or IC2 is defective. or IC11 or IC14 is defective. Paper feed is abnormal. Checkpoint Check input signal waveform at 8 pin on the both IC11 and IC14. Check output signal waveform at 1 and 15pin on the both IC11 and IC14.(CH1) Solution If the input signal is not correct, replace IC1 or IC2. ( or replace the main borad) If the input signal is correct and the output signal is not correct, replace the IC11. IC1 is defective. No data is printed. Check the output signal waveform at pin 15 of IC1. If this signal is not output, replace IC1. ( or replace the main board) A particular dot fails to print. IC2 is defective. or One of the head drive transistors is defective (Q1 ~ Q24). Check the voltage waveform (CH1) at pin 69 and pins 76 ~ 89, pins 91~ 99 of IC2. Check the voltage waveform (CH2) for each transistor. If the head drive signal is not output, replace IC2.( or replace the main board) If the head drive signal is output from the head drive transistors, replace the head drive transistor. Rev.A 5-15

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16
  • 17
  • 18
  • 19
  • 20
  • 21
  • 22
  • 23
  • 24
  • 25
  • 26
  • 27
  • 28
  • 29
  • 30
  • 31
  • 32
  • 33
  • 34
  • 35
  • 36
  • 37
  • 38
  • 39
  • 40
  • 41
  • 42
  • 43
  • 44
  • 45
  • 46
  • 47
  • 48
  • 49
  • 50
  • 51
  • 52
  • 53
  • 54
  • 55
  • 56
  • 57
  • 58
  • 59
  • 60
  • 61
  • 62
  • 63
  • 64
  • 65
  • 66
  • 67
  • 68
  • 69
  • 70
  • 71
  • 72
  • 73
  • 74
  • 75
  • 76
  • 77
  • 78
  • 79
  • 80
  • 81
  • 82
  • 83
  • 84
  • 85
  • 86
  • 87
  • 88
  • 89
  • 90
  • 91
  • 92
  • 93
  • 94
  • 95
  • 96
  • 97
  • 98
  • 99
  • 100
  • 101
  • 102
  • 103
  • 104
  • 105
  • 106
  • 107
  • 108
  • 109
  • 110
  • 111
  • 112
  • 113
  • 114
  • 115
  • 116
  • 117
  • 118
  • 119
  • 120
  • 121
  • 122
  • 123
  • 124
  • 125
  • 126
  • 127
  • 128
  • 129
  • 130
  • 131
  • 132
  • 133
  • 134
  • 135
  • 136
  • 137
  • 138
  • 139
  • 140
  • 141
  • 142
  • 143
  • 144
  • 145
  • 146
  • 147
  • 148
  • 149
  • 150
  • 151
  • 152
  • 153
  • 154
  • 155
  • 156
  • 157
  • 158
  • 159
  • 160
  • 161
  • 162
  • 163
  • 164
  • 165
Table 5-7. Repairing the C186 MAIN Board Assembly
Problem
Cause
Checkpoint
Solution
Paper feed is
abnormal.
IC1 is defective.
or
IC2 is defective.
or
IC11 or IC14 is
defective.
Check input signal waveform at 8 pin
on the both IC11 and IC14.
Check output signal waveform at 1 and
15pin on the both IC11 and IC14.(CH1)
If the input signal
is not correct,
replace IC1 or
IC2. ( or replace
the main borad)
If the input signal
is correct and the
output signal is
not correct,
replace the IC11.
No data is
printed.
IC1 is defective.
Check the output signal waveform at pin
15 of IC1.
If this signal is
not output,
replace IC1.
( or replace the
main board)
A particular
dot fails to
print.
IC2 is defective.
or
One of the head drive
transistors is defective
(Q1 ~ Q24).
Check the voltage waveform (CH1) at
pin 69 and pins 76 ~ 89, pins 91~ 99 of
IC2.
Check the voltage waveform (CH2) for
each transistor.
If the head drive
signal is not
output, replace
IC2.( or replace
the main board)
If the head drive
signal is output
from the head
drive transistors,
replace the head
drive transistor.
LQ-2070 Service Manual
Troubleshooting
Rev.A
5-15