
B-70255EN/01 6.TROUBLESHOOTING
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Type of alarm Source Major causes
RFI This alarm is issued if a high RF current
flows through the discharge tube when
the oscillator is operating in CW/pulse
mode.
If the power supply unit fails just because the high-speed diode or
FET module is damaged, the power supply unit can be repaired by
component or PCB replacement. Other adjustments are not required.
If the power supply unit itself is replaced, power supply adjustments
are required after aging.
6.4.2 Power Supply Cannot Be Switched Off Using CRT/MDI Switch
The power supply cannot always be switched. It can be switched only
before the switching on of RUN (pressure control start) or after the
completion of purge with RUN off and the PURGE lamp lit.
6.4.3 Power Supply Cannot Be Switched On Using CRT/MDI Switch
Non-fuse breaker for IF PCB is tripping.
6.4.4 Laser Output Just After Switch On Is Low
(1) The cooling water temperature is not normal, although the chiller
unit is operating. This phenomenon may be caused when the
ambient temperature is low. In such a case, the specified
temperature will be set in five to ten minutes after the unit starts.
So, perform activation again.
(2) Slight leakage exists in the tube between laser and gas cylinder.
This is the case in which the laser output in the first run after a
long halt is low and becomes normal after the second run. Check
for leakage, loose fixing or crack. Correct the tube and fitting if
any anomaly exists.
6.4.5 Display of Fluctuating Laser Output On CRT
First check if PRM No. 15216 is taking the value of 60, which is a
standard. In case the fluctuation continues with this value used, read
the laser output monitor value indicated in DGN=906. Its range of
fluctuation is smaller than ±50. If it exceeds this value, check the
followings.
(1) Is the coaxial cable between the laser power sensor mounted on
the rear mirror holder and the relay PCB B (A16B-1600-0361) or
the cable between the relay PCB B and the IF PCB (A16B-2100-
0141) inside the laser oscillator fixed tightly?
(2) Is there anomaly in the laser power sensor output? Is the DC
resistor between the terminals of the power sensor unit in the
range 100W-500W?
(3) Check the input signal (LPWI-0V) of the relay PCB B.