
B-70255EN/01 6.TROUBLESHOOTING
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Cause of trouble Solution
1 Lack of output from
laser power sensor
unit
The thermocouple inside the power sensor unit may
be damaged, or there may be a poor terminal
connection. Measure the direct current resistance
between the terminals of the power sensor unit, and
check that the measured value falls within 100 to
500 ohms. If the measured value falls outside this
range, replace the power sensor unit.
2 Connecting anomaly
of the cable of laser
power sensor unit.
Check whether the cable is securely connected to
the power sensor unit. If not, reattach the cable.
3 Anomaly of
intermediate PCB B
(A16B-1600-0361)
If the above checks do not reveal any abnormality,
and there is no output from intermediate PCB B,
replace the PCB.
ALM No.4077
Overheat of beam absorber
Laser beam is introduced into the beam absorber, when the
oscillation takes place with shutter closed. This absorber is
water-cooled and sends alarm when the temperature of the
absorber exceeds a critical one. In the usual operation, the
irradiation of the absorber takes place only during the calibration
after the oscillator start.
Alarm output condition
This alarm is issued when the absorber temperature signal becomes 0
during the time from RUN-ON to immediately before purge completion.
Absorber temperature signal
ABT (bit 7 at address 01H of DI of the laser interface)
Related parameters
DGN.961#7 *ABT Absorber temperature switch
Cause of trouble Solution
1 Insufficient cooling
water
The amount of cooling water being supplied to the
beam absorber may be insufficient. Check whether
the cooling water tube between the water branch
unit and beam absorber is clogged. If the tube is
clogged, replace the tube.
2 Temperature sensor
wired incorrectly
Check if the cable is securely connected to the
temperature sensor. If not, reattach the cable.
3 Temperature sensor
abnormal
The temperature sensor is designed to be
actuated by temperatures of 80°C or higher. If the
temperature sensor is actuated at lower
temperatures, replace the sensor.
4 Absorber abnormal If the temperature rises when water is flowing,
replace the absorber.
ALM No.4078
Gas pressure anomaly in discharge tube
The gas pressure is monitored after the discharge start ready
condition (LRDY) is established. This alarm is issued, if the
monitored gas pressure deviates by
±100 (1330Pa) from the set
gas pressure.