Epson LQ-1170 Service Manual page 106

Table 5-5. R
Symptom
Problem
The CPU does
The printer
not operate.
does not op-
erate at all.
The carriage
carriage
does not op-
operates
erate at all.
Carriage oper-
ation is unsta-
ble (lack of
torque).
air of in the Main/Drive Circuit Board (Continued)
Cause
Either ROM or
RAM is
defective.
The CPU is Check the oscillator signal at either pin 33
defective. or pin 34 of the CPU.
Check the CR motor phase signal at pins
defective.
9, 10, 11, and 12 of IC2C.
At IC 15,
ICI 5 is
defective and the output waveform for pin 8.
IC
is
defective.
5 - 1 7
Checkpoint
check the input signal for pin 6
Solution
Replace IC3A
or IC4A.
If a signal is
detected, re-
place IC2C.
Otherwise, re-
place CR1.
Replace IC2C.
Replace IC 15.
Replace IC 15.