The output terminals are always electrically “hot, Troubleshooting & repair, Caution – Lincoln Electric IDEALARC R3R-500 User Manual
Page 42
TROUBLESHOOTING & REPAIR
F-8
F-8
IDEALARC R3R
Observe Safety Guidelines
TROUBLESHOOTING GUIDE
detailed in the beginning of this manual.
CAUTION
If for any reason you do not understand the test procedures or are unable to perform the test/repairs safely, con-
tact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed. Call
216-383-2531 or 1-800-833-9353.
PROBLEMS
(SYMPTOMS)
POSSIBLE AREAS OF
MISADJUSTMENT(S)
RECOMMENDED
COURSE OF ACTION
OUTPUT PROBLEMS
The output terminals are always
electrically “hot.”
1. This is a normal condition. The
open circuit voltage should be
approximately 67VDC. The
open circuit voltage may vary
with the input line voltage.
The machine welds but reduces to
a low output under load and
remains there until the load is
removed and the arc re-started.
1. Operating the machine beyond
the current rating will cause the
overload protection circuit on
the control board to phase-
back the machine to a low out-
put.
1. Check the output shunt for
loose or faulty connections.
2. The output shunt may be faulty.
Replace.
3. The control board may be faulty.
Replace.
The machine shuts off even when
not under load or makes excessive
noise like it is loaded.
1. Make sure the fan motor and
blades are operating properly.
2. Perform the Main Transformer
3. Check the latching resistor R3.
Normal resistance is 40 ohms.