Lincoln Electric IM481-B - Manual (Page 24)

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Trouble Cause What To Do
Machine has low output and no con-
trol.
Machine does not have maximum
output.
Machine will not shut off.
Variable or sluggish welding arc.
Output control not functioning on the
machine.
1. Output Control “Local-Remote”
switch (S2) in wrong position.
2. Output Control switch faulty.
3. Open in feedback circuitry.
4. Faulty Control PC Board.
5. Output control potentiometer cir-
cuit open (Lead 75).
1. One input fuse blown.
2. One phase of main transformer
open.
3. Faulty Control PC Board.
4. Output control potentiometer
defective.
5. Output control potentiometer
Leads 210, 211, or 75 open.
1. Input contactor contacts frozen.
2. Defective Power “I/O”
switch, (S1).
1. Poor work or electrode connec-
tion.
2. Welding leads too small.
3. Welding current or voltage too
low.
4. Defective main SCR bridge.
1. Output Control “Local-Remote”
switch (S2) in wrong position.
2. Faulty Output Control switch.
3. Faulty Output Control potentiometer.
4. Leads or connections open in
control circuit.
5. Faulty Control PC Board.
1. Check position of switch.
2. Check switch and replace if
faulty.
3. Check wiring and control PC
Board wiring harness plugs.
4. Replace. See Procedure for
Replacing PC Boards.
5. Check and replace potentiometer
if faulty. Check wiring of Lead
#75.
1. Check and replace if blown after
checking for reason for blown
fuse.
2. Check for open and repair.
3. Replace. See Procedure for
Replacing PC Boards.
4. Check and replace if faulty.
5. Check and repair broken leads.
1. Check and replace if necessary.
2. Replace.
1. Check and clean all connections.
2. Check table in instruction manual.
3. Check procedures for recom-
mended settings.
4. Check and replace if defective.
1. Place switch in “Local”.
2. Check and replace if found faulty.
3. Check and replace if found faulty.
4. Check lead continuity and con-
nections for an open and repair if
necessary.
5. Replace. See Procedure for
Replacing PC Boards.