88
Any abnormality suggests an incorrect D/A voltage from the CPU PCB.
V
CP18
= set voltage (V)
A voltage in the range set voltage ±10% is normal. If abnormal, check the voltage V
CP19
.
If V
CP19
is not in the range +1 to +15V, the IS CTRL PCB is probably defective.
If the V
CP19
voltage is in the normal range but V
CP18
≠set voltage, the filament wiring is
probably touching another electrode inside the vacuum vessel.
6. Checking the heater circuit
The ion-source heater operates on 24VDC.
No temperature rise when the ion-source temperature is set and the heater should be
operating could be due to a heater discontinuity, short-circuit, disconnected wiring, or
incorrectly installed heater temperature sensor. Follow the procedure below to diagnose
problems with the heater.
Check that the CP2 voltage = +19±1V.
If abnormal, replace IS CTRL-A.
Measure the voltage applied to the heater at the feedthrough contacts on the IS CTRL-A
PCB.
HT+ Heater + voltage (0 to +24V) Approximately 24V during heating.
HT- Heater - voltage (0V)
The IS CTRL-A PCB is normal if a voltage is applied to HT+.
If the voltage at HT is approximately 0V, a short-circuit has probably occurred in the vacuum
vessel.
Turn off the heater with the tool program
. (The sound of the relay on IS CTRL-A operating
should be audible.) Check that the voltage at HT+ is 0V, and then measure the resistance
across HT+ and HT- using the tester resistance mode.
A resistance of 15 to 25Ω is normal. Be aware of the polarity when measuring the
resistance; correct measurement is only possible by applying a positive voltage to HT+ and
a negative voltage to HT-. If the polarity is unknown, turn off the instrument power, remove
IS CTRL-A to eliminate the influence of its circuits and measure the resistance directly at the
feedthrough terminals.
Observe the CP1[PWM] waveform with an oscilloscope.
This is normal if an ON/OFF PWM waveform between 19 and 24V is observed, and the HT+
output voltage is approximately proportional to the duty ratio of the PWM waveform (0 to
100%: 0 to 24V).
An abnormal PWM waveform suggests a defective CPU PCB or MAIN CTRL-A PCB.
7. Checking the ion-source temperature measurement circuit
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