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...

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...

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...

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...

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...

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...

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...

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...

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...

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...