Troubleshooting

Table 3-5. Printhead Driver Test Points

 

Transistor

Test Method

 

 

Numbers

(Set Meter to Diodes. Check with Printer Power Off.)

Meter Reading

 

 

 

 

 

Q2, Q4, Q5

Emitter and base are marked on the CO94 MAIN board.

Consistent readings for all

 

Q6, Q8, Q9

Check from base to collector, from base to emitter, and

transistors, within YZ 20%.

 

Ql 0, Ql 1, Q12

from emitter to collector. Reverse leads and test again.

Not open and not shorted

 

 

 

between base and collector

 

 

 

 

Q3, Q7, 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.

 

 

‘in Numbers

Check with Printer Power Off.)

Meter Reading

 

 

 

 

1, 8,

Pins 1 and 18 are marked on board. All odd

Consistent readings from all pins within f 20%.

 

ll,and18

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

 

SLA7024M

- lead on each of the four pins.

consistency.)

 

 

 

 

 

PF Motor

Test Method

 

 

Driver (El)

(Set Meter to Diodes.

 

 

‘in 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 f 20%

 

9 on chip

+ lead on pin 1 (ground), and count over

Not open and not shorted. (The typical reading

 

UPA1476H

to find each of the four pins to be checked.

is .672, but consistency is most important.)

 

 

 

 

 

 

Test Method

 

 

PF

(Set Meter to Diodes.

 

 

Transistor

Check with Printer Power Off.)

Meter Reading

 

 

 

 

 

Q15

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.

 

 

 

 

 

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3-4

E p s o n FX-870/1170