Epson LX-300 Service Manual page 79

Troubleshooting
Head
6 8 4 9 2
Figure 5-2. Printhead Connector Pin Alignment
Table 5-2. Printhead Driver Test Points
Transistor
(Set Meter to Diodes. Check with Power Off.)
Numbers
I
Check from base to collector.
Q1 ,Q2,Q3,Q4
Transistor
(Set Meter to Diodes. Check with Power Off.)
Numbers
Check from base to collector and from base to
PF Motor Driver emitter.
Reverse leads and test again.
(Emitter and base are marked on the main board
5-2
Pin No.
C C
View A
Test Method
Table 5-3. Motor Driver Test Points
Test Method
LX-300 Service Manual
7
C : COMMON
Meter Reading
Not open and not shorted
from base to collector, base
Meter Reading
Neither open nor shorted
from base to collector or
base to emitter.
I