Tweco 400 MST Arc Master - Manual (Page 44)

400MST
9
ADVANCED TROUBLESHOOTING
9 – 7
between CN1 on PCB16 and CN2 on PCB3.
• Contact the manufacturer if you find any bro-
ken connectors or damaged wiring har-
nesses.
c) Verify PCB4 (WK-4819) for burned or discol-
ored components or printed circuit board.
• Confirm that the PCB is securely fastened in
place. (No loose screws).
• Refer to section 9.2.4.4 for the replacement
of PCB4.
1.2.10 E85 "Pre-Charge Error"
Cause
Occurs, after you apply power, when a failure is
detected during the preliminary charging of the
capacitors.
Verification/Remedy
a) Verify the AC input voltage and the Capacitor
Bus Voltage on PCB2 (WK-5597).
• Follow the instruction in section 9.1.4.2.
b) Verify the input diode, D1.
• Refer to section 9.1.4.5 for the test and
replacement of D1.
c) Verify the IGBT, Q1-Q24.
• Refer to section 9.1.4.7 for the test and
sections 9.2.4.7 and 9.2.4.8 for replacement of
Q1, Q2, ..., Q23, and Q24.
d) Replace PCB2 (WK-5597) and PCB4 (WK-
4819).
• If the tests in the above sections (a, b, c) are
within expected results and the unit is still
defective, replace PCB2 and PCB4.
• Refer to section 9.2.4.2 and 9.2.4.4 for the
replacement of PCB2 and PCB4.
1.2.11 E94 "Thermistor Failure"
Cause
Occurs when the thermistor for the temperature
detection circuitry is open.
Verification/Remedy
a) Verify the wiring harness and connection
between CN8 and CN9 on PCB6 (WK-5688)
and thermistors TH1 and TH2.
• Confirm a secure connection of the harness
wired between CN8 and CN9 on PCB6 and
TH1 and TH2 and re-install the harnesses
with a secure connection.
• Contact the manufacturer if you find any bro-
ken connectors or damaged wiring har-
nesses.
b) Replace thermistors, TH1 and TH2.
• Refer to section 9.2.4.17 and 9.2.4.18 for the
replacement of TH1 and TH2.
c) Replace PCB6 (WK-5688).
• Refer to section 9.2.4.6 for the replacement
of PCB6.
1.2.12 E99 "Initial Power Receiving"
Cause
Occurs when the initial AC power-received signal
has not reached the CPU.
NOTE
This error occurs normally during the power "OFF"
sequence of the unit.
Verification/Remedy
a) Verify the wiring harness and connection of
CN1 on PCB16 (WK-4917) and CN2 on PCB3
(WK-5548).
• Confirm a secure connection of the harness
wired between CN1 on PCB21 and CN2 on
PCB3 and re-install the harness with a
secure connection.
• Contact the manufacturer if you find any bro-
ken connectors or a damaged wiring harness.
b) Verify and replace PCB4 (WK-4819).
• During the installation of PCB4 and PCB3,
confirm that the PCB's are securely fastened
in place. (No loose screws).
• Refer to section 9.2.4.4 for the replacement
of PCB4.
c) Replace PCB6 (WK-5688).
• Refer to section 9.2.4.6 for the replacement
of PCB6.