
B-70255EN/01 6.TROUBLESHOOTING
- 63 -
Phenomenon Presumption cause
5 The RF voltage of all the units is high during
discharge and the laser power is low. The
discharge tends to disappear. When the purge
is repeatedly performed, the RF voltage
gradually decreases and the laser power
recovers.
This phenomenon often appears after the laser
was not used for a long period.
The external laser gas
pipe is abnormal.
The gas composition
is not normal due to
leakage of a gas.
6 The RF voltage of all the units is high during
discharge and the laser power is low. The
discharge is tends to disappear. Even though
the purge is repeatedly performed, the situation
does not recover.
Internal leakage of
oscillator
Internal leakage of
water of the oscillator
7 The RF voltage of all the units is high during
discharge but the laser power is normal. The
discharge is tends to disappear. The output is
high for the high output command, and it is
lower than the standard for the low output
command.
The intra-tube
pressure of the laser
gas is high or the gas
composition is not
normal (excessive
amount of N
2
).
8 The RF voltage of all the units is low during
discharge and the laser power is low. The
discharge is widely spread. In the high laser
power region, the power is low but in the low
power region, it is higher than the normal value.
The alarm is DCV alarm.
The intra-tube
pressure of the laser
gas is high or the gas
composition is not
normal (excessive
amount of He).
9 Although the RFV, RFI, and output are normal,
an alarm may occur.
Anomaly of the Laser
power-supply unit
itself (anomaly of
alarm circuit).
(3) Solution
Cause of trouble Solution
1 IF PCB abnormal Replace the IF PCB.
2 Laser power supply
abnormal
Locate the faulty component, then replace it.
3 Laser power supply
maladjusted
Adjust the laser power supply as explained in
Chapter 9.
4 External laser gas
pipe abnormal
Identify the faulty location, then repair the
external pipe as explained in Chapter 4.
5 Laser gas
composition ratio
abnormal
Replace the laser gas with one that satisfies the
specifications. If there is a leakage in the
external piping and a gas cylinder is attached to
the piping for a long time, the gas composition
may have changed.
6 Pressure sensor
abnormal
Replace the pressure sensor.
7 Internal leakage,
leakage of water
Check the faulty location, and replace the faulty
part so that the leakage is within the allowable
range (not more than 10/15 minutes set as the
amount of change in DGN. 905).