CIGWELD TRANSTIG 300 AC/DC, Service Manual, Page: 69 / 134

1
3
ADVANCED TROUBLESHOOTING
c) Verify the no-load voltage (OCV).
(Applies to STICK, High Frequency TIG (HF
TIG) mode.)
Refer to the section "Verification of No-load
voltage (OCV)" in section 1
3
.5.9.
If performing the "No-Load Voltage Failure"
procedure does not rectify the failure, perform
the following tests in the sequence below.
Replace any defective components found.
1. Secondary IGBT (Q25-Q26)
Verification. Refer to section 1
3
.5.8.
Replacement. Refer to section 1
4
.3.33.
2. Secondary diode (D2-D7)
Verification. Refer to section 1
3
.5.6.
Replacement. Refer to section 1
4
.3.32.
3. Coupling coil (CC1)
Replacement. Refer to section 1
4
.3.20.
4. Reactor (FCH1)
Replacement. Refer to section 1
4
.3.21.
5. PCB14 (T1-T2)
Replacement. Refer to section 1
4
.3.11.
6. Primary IGBT (Q1-Q24)
Verification. Refer to section 1
3
.5.7.
Replacement. Refer to section 1
4
.3.7,
1
4
.3.8.
7. Hall C.T. (HCT1)
Replacement. Refer to 1
4
.3.30.
13.
3.4 "Operating Panel Failure"
(LED's do not light properly
or welding setting cannot be
established.)
Cause
Occurs when there is a connection failure among
PCB6 (WK-5549), PCB12 (WK-5527) and PCB6
or PCB12 are defective.
Verification/Remedy
a) Verify the harness connection between CN21
on PCB6 (WK-5549) and CN2 on PCB12
(WK-5527).
Confirm a secure connection of the harness
and the connections between CN21 on PCB6
(WK-5549) and CN2 on PCB12 (WK-5527).
Contact the manufacturer if you find any bro-
ken connectors or a damaged wiring har-
nesses.
b) Verify the connection between PCB5
(WK-5551) and PCB6 (WK-5549).
c) Replace PCB5 (WK-5551) and PCB6 (WK-
5549).
Refer to section 1
4
.3.5, 1
4
.3.6.
d) Verify the connection between PCB6 (WK-
5549) and PCB12 (WK-5527).
e) Replace PCB6 (WK-5549) and PCB12
(WK-5527).
Refer to section 1
4
.3.6, 1
4
.3.9.
13.
3. 5 "High Frequency Output Fail-
ure" (Unit does not generate
High Frequency.)
Cause
Occurs when the HF. unit (HF UNIT1) is defective
or blown.
Verification/Remedy
Caution
Read and understand this entire section before
proceeding. Extreme personal harm and test
equipment damage will occur if the procedures are
not performed accurately. The unit will generate a
High Voltage component that can cause extreme
personal harm and test equipment damage.Capac-
itors installed inside the Welding Power Source are
electrically charged for a while after the Mains ON/
OFF switch or distribution panel switch has been
turned off. Before inspecting the inside of the Weld-
ing Power Source, leave it for about 5 min. after
switching off power for discharging the capacitors,
and then remove the top and side panels.
a) Verify the connection between High Frequency
(HF UNIT1) and Coupling Coil (CC1).
Verify the connection between the HF UNIT1
and CC1; confirm that the quick-disconnect
terminals are inserted onto the terminals of
HF UNIT1 (TB5-TB6) correctly and com-
pletely.
Confirm there are no short circuits, burnt or
broken wires at CC1.
Replace CC1.
Refer to section 1
4
.3.20.
June 30, 2008 13-9
SERVICE MANUAL TRANSTIG 300 AC/DC