Epson LX-300 Service Manual

Troubleshooting
LX-300 Service Manual
Printhead
Head Pin No.
68492 CC C351 7
View A
C : COMMON
Figure 5-2. Printhead Connector Pin Alignment
Table 5-2.
Printhead Driver Test Points
Transistor
Test Method
Numbers
(Set Meter to Diodes. Check with Power Off.)
Meter Reading
I
Q1 ,Q2,Q3,Q4
Check from base to collector.
Not open and not shorted
Q5,Q6,Q7,Q8,
Check from base to emitter.
from base to collector, base
I Q9
I Reverse leads and test again.
I to emitter.
I
Table 5-3. Motor Driver Test Points
Transistor
Numbers
PF Motor Driver
(Q11,Q12,Q13,
Q14)
Test Method
(Set Meter to Diodes. Check with Power Off.)
Check from base to collector and from base to
emitter.
Reverse leads and test again.
(Emitter and base are marked on the main board
assemblv.)
Meter Reading
Neither open nor shorted
from base to collector or
base to emitter.
H ..,,,
l!’
-. ..
5-2
Rev.A

Epson LX-300 Specifications

General

Print Method	9-pin impact dot matrix
Interface	Parallel
Paper Handling	Friction feed, tractor feed
Weight	4.4 kg
Operating Environment	Temperature: 5 - 35°C, Humidity: 10 - 80%