Epson FX-870/1170 User Manual
Page 57
Troubleshooting
Table 3-5. Printhead Driver Test Points
Transistor
Test Method
Numbers
(Set Meter to Diodes. Check with Printer Power Off.)
Meter Reading
Emitter and base are marked on the CO94 MAIN board.
Consistent readings for all
Q6,
Check from base to collector, from base to emitter, and
transistors, within 20%.
0, 1, Q12
from emitter to collector. Reverse leads and test again.
Not open and not shorted
between base and collector
Q13
and base and emitter.
Table 3-6. Carriage and Paper Feed Motor Driver Test Points
CR Motor
Test Method
Driver (IC6)
(Set Meter to Diodes.
Numbers
Check
Printer Power Off.)
Meter Reading
Pins 1 and 18 are marked on board. All odd Consistent readings from all pins within 20%.
pins are on one side, and even are on the
Not open and not shorted. (The typical reading
on chip
other. Place + lead on pin 4 (ground) and
is 547, but the reading is not as important as
lead on each of the four pins.
consistency.)
PF Motor
Test Method
Driver
(Set Meter to Diodes.
Numbers
Check with Printer Power Off.)
Meter Reading
3, 5, 7, and
Pins 1 and 10 are marked on board. Place
Consistent readings from all pins within 20%
9 on chip
+ lead on pin 1 (ground), and count over
Not open and not shorted. (The typical reading
to find each of the four pins to be checked.
is
but consistency is most important.)
Test Method
PF
(Set Meter to Diodes.
Transistor
Check with Printer Power Off.)
Meter Reading
Emitter and base are marked on board.
Consistent readings for all transistors, within
Check from base to collector, from base to
20%. Not open and not shorted between
emitter, and from emitter to collector.
base and collector and base and emitter.
Reverse leads and test again.
3-4
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