Lincoln Electric NA-5N Service Manual page 83

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Observe all Safety Guidelines detailed throughout this manual
PROBLEMS
(SYMPTOMS)
The circuit breaker trips after the
wire has been feeding for a period of
time. Welding is normal.
The 1/8 amp fuse on the voltage
board repeatedly fails.
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. Check to make sure there are not
any mechanical restrictions in the
wire feeding path which could
cause excessive loading on the
wire drive motor.
1. Check to make sure the PC
boards are NOT grounded to the
case of the NA-5. This can hap-
pen due to metallic dust build-up.
CAUTION
NA-5
RECOMMENDED
COURSE OF ACTION
1. Perform the DC Power Supply
Test.
2. Perform the Wire Drive Motor
Test.
3. The power board may be faulty.
1. Remove the input power to the
NA-5 and replace the 1/8 amp
fuse. Locate and remove the #21
and #67 leads from the TS1 ter-
minal strip.
A. Make a resistance check
from the following leads
to the NA-5 case ground-
ing screw. Lead #510A,
510P, 500, 515 and 525.
B. The resistances should
be above 1000 ohms. If
any tests are below 1000
ohms that circuit has low
resistance to case
ground. Isolate faulty
leads or PC board. See
wiring diagram and
schematic.
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