Lincoln Na5 Service Manual

							F-48TROUBLESHOOTING & REPAIRF-48
NA-5
TEST DESCRIPTION
This test will determine if the wire drive motor is able to function whe\
n supplied with the cor-
rect voltages..
MATERIALS NEEDED
Variable DC voltage supply 0  to 90 VDC
Isolated DC voltage supply 0  to 120 VDC
Volt/Ohmeter
WIRE FEED DRIVE MOTOR TEST
Service and repair should be performed only by Lincoln Electric factory trained per-
sonnel. Unauthorized repairs performed on this equipment could result in danger to
the technician or the machine operator and will invalidate your factory warranty. For
your safety and to avoid electrical shock, please observe all safety notes and precau-
tions detailed throughout this manual.
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 (800) 833-9353 (WELD).
_____________________________________________________________
WARNING
This procedure takes approximately 17 minutes to perform.
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							F-49TROUBLESHOOTING & REPAIRF-49
TEST PROCEDURE
1. Remove the wire feed motor connec-
tor from the NA-5 control box.
2. Using the ohmmeter, measure the
resistances per the table below. Also
see Figure F.5.
3. If the motor resistance test is good,
proceed to the 
Motor Applied Voltage
Test
.
MOTOR APPLIED 
VOLTAGE TEST
1. Carefully connect the isolated 120 VDC supply  (SUPPLY TURNED
OFF) to pins C and D on the motor
connector.
2. Carefully connect the variable 0 to 90 VDC supply  (SUPPLY TURNED
OFF) to pins A and B on the motor
connector. (See Table F.1.)
3. Apply field voltage first (pins C and D) to the motor. Then, slowly apply
the armature voltage to pins A and B.
(See Table F.1).
4. The motor should run, and the speed should vary with changes to the
armature voltage.
5. If the motor does NOT run and change speed correctly, the motor or
gear box may be faulty.
6. To stop the motor,  REMOVE THE
ARMATURE VOLTAGE FIRST (pins
A and B).
WIRE FEED DRIVE MOTOR TEST(Continued)
NA-5
TEST POINTS
RESISTANCE DC VOLTAGE
Lead #539 to lead #541 4 to 5 ohms 0 to 90 VDC
armature
Lead #626 to lead #627 750 to 850 ohms 90 to 120 VDC
field winding
All leads 500,000 ohms  NONE
to min.
motor shell
(Except lead #67)
Lead #67 to motor  zero ohmsNot Applicable
shell
FIGURE F.5  WIRE FEED DRIVE MOTOR CONNECTOR PINS.
FA
B
C
D
E
#541
#539
#67
#627
#626
MOTOR
CONNECTOR
PINS
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							F-50TROUBLESHOOTING & REPAIRF-50
NA-5
TEST DESCRIPTION
This test will help the technician to determine if the external voltage \
sensing leads are con-
nected properly and intact.
MATERIALS NEEDED
Volt-Ohmmeter (Multimeter)
5/16 Nutdriver
3/4 wrench
Wiring diagram
EXTERNAL RESISTANCE TEST (LEADS #21 AND #67)
Service and repair should be performed only by Lincoln Electric factory trained per-
sonnel. Unauthorized repairs performed on this equipment could result in danger to
the technician or the machine operator and will invalidate your factory warranty. For
your safety and to avoid electrical shock, please observe all safety notes and precau-
tions detailed throughout this manual.
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 (800) 833-9353 (WELD).
_____________________________________________________________
WARNING
This procedure takes approximately 8 minutes to perform.
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							F-51TROUBLESHOOTING & REPAIRF-51
PROCEDURE
1.  Make sure the electrode wire is fedthrough the wire contact assembly
tip but NOT touching the work
piece.
2.  Disconnect input power to the NA-5.
3.  Make sure the drive motor cable and power source control cables are
properly connected to the NA-5 con-
trol box. 
4.  Using the 5/16 nutdriver open the control box PC board access door.
5.  Locate the TS1 terminal strip.  See wiring diagram.  6.  Using the ohmmeter check the resis-
tances per the following table F.2
7.  Reconnect the welding cable leads to the contact assembly.
8.  If any of the resistances are not cor- rect per Table F.2  check the associ-
ated leads, cables and circuits for
opens or shorts.  See wiring dia-
gram.
9.  Close and secure the control box access door.
EXTERNAL RESISTANCE TEST (LEADS #21 AND #67)(Continued)
NA-5
TEST POINTS EXPECTED  COMMENTS AND 
RESISTANCES CONDITIONS
Lead #667 Zero or less than Electrode wire must be in to 1 ohm contact assembly tip
Electrode wire
Lead #621 to  Zero or less than Polarity switches must be  work piece 1 ohm in the correct positions
Lead #667 to Greater than 15K Using the 3/4 wrench #621 ohms disconnect the welding cable(s) from the
contact assembly
TABLE F.2  EXTERNAL VOLTAGE SENSING LEADS TEST POINTS
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							F-52TROUBLESHOOTING & REPAIRF-52
NA-5
TEST DESCRIPTION
This test will help determine if the out-of-voltage range shut down circ\
uitry is functioning prop-
erly.
MATERIALS NEEDED
5/16 Nutdriver
Jumper wire
Lincoln CV Power Source
OUT OF VOLTAGE RANGE SHUT DOWN TEST
Service and repair should be performed only by Lincoln Electric factory trained per-
sonnel. Unauthorized repairs performed on this equipment could result in danger to
the technician or the machine operator and will invalidate your factory warranty. For
your safety and to avoid electrical shock, please observe all safety notes and precau-
tions detailed throughout this manual.
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 (800) 833-9353 (WELD).
_____________________________________________________________
WARNING
This procedure takes approximately 18 minutes to perform.
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							F-53TROUBLESHOOTING & REPAIRF-53
TEST PROCEDURE
1.  Remove input power to the NA-5
2.  Using the 5/16 nutdriver open thecontrol box PC board access door.
3.  Locate the voltage PC board. Jumper together the BYPASS and
“Common” pins on the NA-5 voltage
PC board.  See Figure F.6  (On older
voltage boards these pins may be
labeled B).  This should disable the
shut down circuit. 4.  Connect to a Lincoln Electric CV
power source per connection dia-
gram.  See the 
Installation  section
of this manual.
OUT OF VOLTAGE RANGE SHUT DOWN TEST (Continued)
NA-5
FIGURE F.6   VOLTAGE BOARD AND PIN LOCATIONS
NA-5
VOLTAGE
G1556-[ ]
BYPASS
COM
AUTO
JUMPER 
TOGETHER
1/8 AMP  FUSE
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							F-54TROUBLESHOOTING & REPAIRF-54
5.  Start welding and observe theACTUAL voltage reading on the NA-
5 digital meter.  The actual voltage
must match the SET voltage within
+/- 0.5VDC.  If it does NOT, the NA-
5 is designed to shut down.
6.  If the NA-5 continues to shut down with the BYPASS pins jumpered
together, the voltage PC board may
be faulty.
7.  If the ACTUAL voltage reading is zero, the sensing leads may be
faulty.  Perform the 
External
Resistance Test
.  Also check the
1/8 amp fuse on the voltage PC
board.
8.  Check the polarity switche in the Lincoln power source and its associ-
ated leads.  Set the switches to the
same polarity as the electrode.  See
the Wiring Diagram. 9.  If the ACTUAL voltage reading is dif-
ferent from the SET voltage reading,
the power source may not be capa-
ble of producing the required arc
voltage, the control cable may be
faulty or misconnected, or the NA-5
voltage PC board may be faulty.
10.  After all tests are complete, remove the input power to the wire feeder
and remove the jumper wire you
placed on the BYPASS pins on
the voltage PC board.   Close and
secure the access door.
OUT OF VOLTAGE RANGE SHUT DOWN TEST (Continued)
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							F-55TROUBLESHOOTING & REPAIRF-55
TACH BOARD FEEDBACK TEST
NA-5
TEST DESCRIPTION
This procedure will aid the technician to determine if the tach board is\
 functioning properly.
MATERIALS NEEDED
5/16 Nutdriver
Phillips head screwdriver
Analog volt/ohmmeter (Multimeter)
Wiring diagram
Service and repair should be performed only by Lincoln Electric factory trained per-
sonnel. Unauthorized repairs performed on this equipment could result in danger to
the technician or the machine operator and will invalidate your factory warranty. For
your safety and to avoid electrical shock, please observe all safety notes and precau-
tions detailed throughout this manual.
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 (800) 833-9353 (WELD).
_____________________________________________________________
WARNING
This procedure takes approximately 10 minutes to perform.
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							F-56TROUBLESHOOTING & REPAIRF-56
PROCEDURE
1.  Remove input power to the NA-5.
2.  Using the 5/16 nutdriver open thecontrol box PC board access door.
3.  Locate leads #510A, #525A and #555 on the control board.
4.  Apply 115VAC to the NA-5 wire feeder at the correct pins.  See
wiring diagram.
5.  Check leads #525A(+) to #510A(-) for the presence of 15VDC.  This is
the supply voltage from the control
PC board to the tach PC board.  If
the voltage is present,  proceed to
the next step.  If the voltage is miss-
ing check the associated wiring and
then perform the 
DC Power Supply
Test
.
6.  With the motor running (activate either inch switches or the start
switch) and check leads #555(+) to
#510A(-) for the presence of between 4.5 - 10.5VDC.  (The motor
must be running.)  This is the feed-
back voltage from the tach PC board
to the control PC board.  This volt-
age is dependent upon motor speed.
7.  If the feedback voltage is missing or does not vary with motor speed, the
tach PC board may be faulty.  Also
check for loose or faulty connec-
tions.
8.  After the completion of the tests remove the 115VAC power and
close and secure the access door.
TACH BOARD FEEDBACK TEST (Continued)
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							F-57TROUBLESHOOTING & REPAIRF-57
NA-5
VOLTMETER ACCURACY TEST
TEST DESCRIPTION
This test will help determine if the NA-5 voltmeter is providing accurat\
e readings.
MATERIALS NEEDED
Digital volt/ohmmeter with at least 3-1/2 digits and +/-0.5% accuracy
Service and repair should be performed only by Lincoln Electric factory trained per-
sonnel. Unauthorized repairs performed on this equipment could result in danger to
the technician or the machine operator and will invalidate your factory warranty. For
your safety and to avoid electrical shock, please observe all safety notes and precau-
tions detailed throughout this manual.
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 (800) 833-9353 (WELD).
_____________________________________________________________
WARNING
This procedure takes approximately 10 minutes to perform.
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