Kyocera KM-4230 - Page 433

2A3/4
3-5-14
Shorted fixing
unit thermistor.
Broken fixing
unit heater con-
trol circuit on
the power
source PCB.
Poor contact of
the connector
terminals.
Defective
power source
PCB.
Defective main
PCB.
Defective toner
sensor.
Poor contact of
the toner sen-
sor connector
terminals.
Developer
problem.
Measure the resistance. If it is
infinite, replace the fixing unit
thermistor.
Replace the power source
PCB.
Check the connection of con-
nectors CN10-5 on the main
PCB and CN4-3 on the power
source PCB, and the continu-
ity across the connector termi-
nals. Repair or replace if nec-
essary.
Check if the zero-crossing sig-
nal is output from CN4-3 on
the power source PCB. If not,
replace the power source
PCB.
Replace the main PCB if C640
is detected while CN4-3 on the
power source PCB outputs the
zero-crossing signal.
Replace the toner sensor.
Reinsert the connector. Also
check for continuity within the
connector cable. If none, rem-
edy or replace the cable.
Replace the developer.
C630
C640
C710
Abnormally high fixing
temperature
• The fixing temperature ex-
ceeds 220˚C/428˚F for 10
s.
• The fixing unit high tem-
perature detection circuit
on the engine PCB detects
an abnormally high tem-
perature.
Zero-crossing signal
problem
• The main PCB does not
detect the zero-crossing
signal (Z CROSS SIG) for
the time specified below.
At power-on: 3 s
Others: 5 s
Toner sensor problem
• The sensor output voltage
is outside the range of 0.5
to 4.5 V during copying or
in maintenance item U130.
• The toner sensor control
voltage cannot be set
within the range in mainte-
nance item U130.
Code Contents
Remarks
Causes
Check procedures/
corrective measures