Kyocera 255b, Service Manual

Page: 139 / 291

2K3/2L3
1-4-15
6000/
6020/
6030/
6050
Com-
bined
Broken fuser heater wire
Abnormally high fuser
thermistor temperature
Broken fuser thermistor
wire
Abnormally low fuser
thermistor temperature Deformed connec-
tor pin. If the I/F connector pins of the fuser unit and
the main unit are deformed owing to foreign
matters, such as paper dusts, replace the
connectors or the units including the con-
nectors.
Defective triac. Remove the power cord and check that the
resistance between terminals T1 and T2 of
the triac TRA51 is of several Mega-Ohms
and not shorted (see figure 1-4-2). If failed,
replace the power source PWB (see page 1-
5-34).
Figure 1-4-2
6400 Zero-cross signal error
While fuser heater control is
performed, the zero-cross sig-
nal is not input within 3 s.
Defective connec-
tor cable or poor
contact in the con-
nector. Reinsert the connector. Also check for conti-
nuity within the connector cable. If none,
replace the cable.
Power source PWB (YC4) and engine PWB
(YC21)
Defective power
source PWB or
engine PWB. Replace the power source PWB or the
engine PWB and check for correct operation
(see page 1-5-34).
7800 Broken external thermistor
wire
The thermistor output value is
0.3 V or less.
Defective connec-
tor cable or poor
contact in the con-
nector. Reinsert the connector. Also check for conti-
nuity within the connector cable. If none,
replace the cable.
Temperature sensor and engine PWB
(YC21)
Defective tempera-
ture sensor. Replace the temperature sensor.
Code Contents Causes
Check procedures/
corrective measures
T1
TRA51
Power source PWB
T2