Verification Of No-Load Voltage (Ocv) - Thermal Arc ARCMASTER 200 TS Service Manual

11
200TS ADVANCED TROUBLESHOOTING
COMPONENT
TESTED
Collector-Emitter
of Q1A~Q2C with
PCB6
Collector-Emitter
of Q3A~Q4C with
PCB7
Table 11-7: Tester checkpoints for Q1A-Q4C
E C
E C
E C
E C
E C
Figure 11-16: Tester checkpoints for Q1A-Q4C
5.8 Verification of No-load Volt-
age (OCV)
CAUTION
Before performing any portion of the procedure
below, make certain the unit is placed in the initial
set up condition as described at the beginning of
an above section "1.Preparation". Refer to section
11.4-1.
TERMINALS
ACCEPTABLE
Positive Negative
VALUE
lead lead
C CE Open
CE C 0.2 to 0.5V
CE E Open
E CE 0.2 to 0.5V
PCB6
E C
E C
E C
E C
E C
PCB7
E C
E C
a) Verify the no-load voltage in STICK mode.
1) In STICK welding mode, mark and then
turn potentiometer VR1 on PCB4 (WK-
5449) all the way to the right and turn off
the electric shock protector function (Volt-
age-Reduction-Device, VRD).
Refer to section 9.
WARNING
Electric shock hazard. The unit will generate OCV
immediately when Process mode is put into the
state of on pushing Process button enabling
STICK mode.
2) Verify the no-load voltage using a DC volt-
meter. (The capability of the voltmeter
should be more than 100VDC.)
3) The normal no-load voltage is approxi-
mately 65V.
b) Verify the no-load voltage (OCV) in High Fre-
quency TIG mode.
WARNING
This welding mode produces high frequency and
high voltage. Extra care shall be taken to prevent
electric shock.
1) When in HF TIG mode, the unit will gener-
ate high voltage. To prevent personal
harm and test equipment damage, mark
and then remove the indicated wire from
the HF UNIT1 shown in Figure 11-18. To
prevent electric shock, always wrap the
removed wire with electrical tape or other
suitable insulation.
Figure 11-17: Removal and installation from the HF
UNIT1
(To disable the operation of the HF unit.)
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