Epson LX-HOO Technical Manual page 114

Problem
The printer does
not operate. (The
power lamp on the
control panel
lights.)
. The l/F cable is
disconnected.
In self-test mode,
printing is
abnormal
A specific dot is
Table 5-5. ROCX Board Unit Repair (Cent'd)
Symptom
Buzzer rigns 5 Home position
times. sensor is
defective.
abnormal.
Carriage control Phase switching is
is abnormal. abnormal.
Common voltage
switching is
defective.
Paper feed con- Phase switching is
trol is abnormal. abnormal.
Common voltage
switching is
defective.
Printhead drive is
missing.
defective.
Cause
Check the level of IC3B
Pin 23.
Carriage at the home
position: LOW
Check the +24V line.
Measure the wave-form
of transistors Q12, 13,
16, 17 collector. Refer to
Figure 2-19.
Check the voltage of
transistor Q19 emitter.
In driving: +24V
In holding +5V
Measure the wave-form
of transistors Q 10, 11,
14, 15 collector. Refer to
Figure 2-25.
Check the voltage of
transistor Q 18 emitter.
In driving: +24V
In holding: +5V
Observe the high/low
change at HDn (Pin 55 -
63) of the IC4B and at
collector of transistor Qn.
5-13
Checkpoint
Replace Gate ar-
ray (3 B).
Replace the re-
(or IC3B).
Replace Q19 (or
Replace the de-
(or IC3B).
Replace Q18 (or
If there are not
high/low
changes, replace
replace any de-
fective
transistors.
REV.-A
Solution