IMA 474
DC-400
Page 23
TROUBLE
CAUSE
WHAT DO DO
L. Poor arc striking with
1. Defective start circuit.
1. Check Start PC Board and reed
semiautomatic or automatic
switch CR3.
wire feeders.
2. Poor work connection.
2. Work connection must be adequate
for application.
3. Improper procedures.
3. Adjust procedures for improved
starting.
4. Defective Control PC Board.
4. Replace. See Procedure for
Replacing PC Boards.
M. Poor arc characteristics.
1. Start circuit energised at all
1. Short reed switch CR3 leads
times (reed switch CR3 not
together. If welding improves,
closing).
replace reed switch.
2. Defective Start PC Board.
2. If problem is still present with reed
switch shorted, unplug Start PC
Board. If problem disappears
replace Start PC Board.
3. Defective Control PC Board.
3. Replace. See Procedure for
Replacing PC Boards.
4. Capacitor(s) in output circuit
4. Replace entire bank of capacitors.
failed. A failure is indicated if
Do not replace individual
the small vent plug on top of a
capacitors.
capacitor is raised or blown out.
WARNING:
The liquid electrolyte in these
capacitors is toxic. Avoid contact
with any portion of your body. Clean
up vented electrolyte using rubber
gloves and a water damped cloth.
Any electrolyte which gets on skin,
clean with soap and wate
r.
N. ARC CONTROL has no
1. Defective R1, L1, S4C, S4D
1. Check and replace if found
effect in CV (FCAW/GMAW)
actuator or S5.
defective. (If S4C or S4D actuator
mode with short circuit
is found defective, replace mode
transfer processes.
switch cam also).
TROUBLESHOOTING (continued)
ARC WELDING SUPPLIES - 07 847 7870
