Lincoln Electric IDEALARK RSR 375-I Operator's Manual page 15

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PROBLEMS
(SYMPTOMS)
C. Machine input contactor closes
but has no or low output. Open
circuit voltage should be 67 to 71
volts.
D. Machine has maximum output
but no control.
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact your Local
Lincoln Authorized Field Service Facility for technical troubleshooting assistance before you proceed.
All manuals and user guides at all-guides.com
TROUBLESHOOTING
Observe all Safety Guidelines detailed througout this manual
POSSIBLE CAUSE
FUNCTION PROBLEMS
1. Electrode or work lead loose or
broken.
2. Open transformer primary or
secondary circuit.
3. Supply line fuse blown.
4. Input line grounded causing
single phase input.
5. Input leads not connected to
contactor.
6. Latching resistor, R3, open.
7. Control circuit problems.
1. Possible defective power SCR.
2. Possible defective control board.
IDEALARC® R3R 375-I, 500-I AND 600-I
CAUTION
RECOMMENDED
COURSE OF ACTION
1. Repair connections.
2. Repair.
3. Replace blown fuse – check fuse
size.
4. Repair input to machine.
5. Connect input lead.
6. a. Replace.
b. Check leads to the resistor
and repair if defective.
7. See Troubleshooting Procedures
– Power Silicon Controlled
Rectifier.
1. Remove all gate leads G1, G2
and G3 at PC board connector
J4. If welder has any open circuit
voltage, power SCR is defective.
See Troubleshooting Procedures
Section J.
2. See PC board Troubleshooting
Procedures Section A
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