Lincoln Electric NA-5N Service Manual page 80

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Observe all Safety Guidelines detailed throughout this manual
PROBLEMS
(SYMPTOMS)
The actual volts reading does NOT
match the set volts reading within a
few tenths of a volt. One reading
may be erratic. The NA-5 does not
shut off.
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric
Service Department for technical troubleshooting assistance before you proceed. Call 216-383-2531 or 1-800-833-9353.
TROUBLESHOOTING & REPAIR
POSSIBLE AREAS OF
MISADJUSTMENTS(S)
FUNCTION PROBLEMS
1. NA-5 units with a G1556-2 (or
higher) voltage board do not con-
trol the actual strike voltage to
match the set strike voltage. The
actual strike voltage is a function
of the set strike voltage and the
OCV contrtol characteristics of
the welding power source.
NA-5 controls with a G1556-3 (or
higher) voltage board must have
the jumper plug connected to the
4-cavity receptacle on the board,
unless the pulsed power filter
board option is connected.
2. Make sure the shutdown
"BYPASS" pins are not jumpered
together on the NA-5 voltage
board.
3. Check the voltage sensing leads
for continuity. (zero ohms). #21
lead should have continuity to the
work piece and #67 lead should
have continuity to the wire feed
head assembly. See wiring dia-
gram.
4. Put the Lincoln welding power
source in the machine control
mode. Check to see if the power
supply can be set for the arc volt-
age required for the process. If
not, the power supply may be
faulty.
CAUTION
NA-5
RECOMMENDED
COURSE OF ACTION
1. If the actual reading is the prob-
lem check the actual volts switch
and associated leads. See wiring
diagram.
2. If the set reading is the problem
check the set volts switch and the
asociated leads. See wiring dia-
gram.
3. Perform the Voltmeter Accuracy
Test
4. Perform the Meter Circuit
Accuraty Test.
5. The voltage board may be faulty.
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