Lincoln Na5 Service Manual

							F-28TROUBLESHOOTING & REPAIRF-28
NA-5
Observe all Safety Guidelines detailed throughout this manual
If for any reason you do not understand the test procedures or are unabl\
e to perform the tests/repairs safely, contact the Lincoln Electric
Service Department for technical troubleshooting assistance before you p\
roceed. Call 216-383-2531 or 1-800-833-9353.
CAUTION
FUNCTION PROBLEMS
PROBLEMS
(SYMPTOMS)POSSIBLE AREAS OF
MISADJUSTMENTS(S)RECOMMENDED
COURSE OF ACTION
The NA-5 repeatedly shutsdown
while welding.  1.  Make sure the power source polarity switch is set for the cor-
rect electrode polarity.
2.  Make sure the #67 and #21 leads are connected to the TS1 termi-
nal strip for the correct electrode
polarity.  See wiring diagram.
3.  Make certain the voltage control switch on the Lincoln CV power
source is set in the “Remote”
position.
4.  Make sure the #21 lead has con- tinuity (zero ohms) to the work
piece.
5.  Make sure the #67 lead has con- tinuity (zero ohms) to the wire
feed head assembly.
6.  Check the 1/8 amp fuse on the NA-5 voltage board.   Replace if
faulty.
7.  The control cable may be faulty. Check or replace.
8.  Be sure the welding power source is compatable with the
NA-5.1. Perform the Out of Voltage
Range Shutdown Test.
2.  The voltage board may be faulty.
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							F-29TROUBLESHOOTING & REPAIRF-29
NA-5
Observe all Safety Guidelines detailed throughout this manual
If for any reason you do not understand the test procedures or are unabl\
e to perform the tests/repairs safely, contact the Lincoln Electric
Service Department for technical troubleshooting assistance before you p\
roceed. Call 216-383-2531 or 1-800-833-9353.
CAUTION
FUNCTION PROBLEMS
PROBLEMS
(SYMPTOMS)POSSIBLE AREAS OF
MISADJUSTMENTS(S)RECOMMENDED
COURSE OF ACTION
The circuit breaker trips when the
inch up, inch down, or start buttons
are pressed.
The circuit breaker trips and or the
fuse (F101) blows when the NA-5 is
turned on. (input power applied).1.  The power board may be faulty. Replace.
1.  Contact your Local Lincoln Authorized Field Service Facility.1.  Perform the Wire Drive Motor
Test.
2.  Perform the DC Power Supply
Test.
1.  If fuse F101 or the circuit breaker- immediately fails when input
power is applied,   unplug all of
the PC boards except the power
board.  If the fuse still fails the
power board may be faulty.   If
the fuse does not fail reconnect
the PC boards one at a time until
the faulty board is located.  Also
check and inspect the wiring har-
ness for “short” or “grounds”.
Reconnect the PC boards in the
following order:  control,
voltage,logic,procedure,option-
timer, remote interface,speedme-
ter and voltmeter.
NOTE:  Some of the above PC
boards are optional and may not
be used in all NA-5 control units.
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							F-30TROUBLESHOOTING & REPAIRF-30
NA-5
Observe all Safety Guidelines detailed throughout this manual
If for any reason you do not understand the test procedures or are unabl\
e to perform the tests/repairs safely, contact the Lincoln Electric
Service Department for technical troubleshooting assistance before you p\
roceed. Call 216-383-2531 or 1-800-833-9353.
CAUTION
FUNCTION PROBLEMS
PROBLEMS
(SYMPTOMS)POSSIBLE AREAS OF
MISADJUSTMENTS(S)RECOMMENDED
COURSE OF ACTION
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. 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.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 checkfrom 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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							F-31TROUBLESHOOTING & REPAIRF-31
NA-5
Observe all Safety Guidelines detailed throughout this manual
If for any reason you do not understand the test procedures or are unabl\
e to perform the tests/repairs safely, contact the Lincoln Electric
Service Department for technical troubleshooting assistance before you p\
roceed. Call 216-383-2531 or 1-800-833-9353.
CAUTION
STARTING/WELDING  PROBLEMS
PROBLEMS
(SYMPTOMS)POSSIBLE AREAS OF
MISADJUSTMENTS(S)RECOMMENDED
COURSE OF ACTION
The arc voltage appears to rise too
slowly.  The wire stubs or blasts off
at the start of the weld sequence.
Once the arc is established the weld-
ing is OK.
The voltage seems too high or flares
excessively at the start of the weld
sequence.  Once the arc is estab-
lished the welding is OK.1.  Increase the strike and or start voltage settings.
2.  Put the output control switch (on  the power source) in the
“Machine Control” position.
Jumper the “BYPASS “ pins on
the NA-5 voltage board.  Control
the arc voltage from the power
source.  If the problem is NOT
remedied the power source may
be at fault.  If the problem is
solved the NA-5 may be at fault.
3.  If the start response jumper, on the voltage board, is in the “B”
position, change to the “A” posi-
tion.  If the “A” position cures the
starting problem the voltage
board may be faulty.
1.  Decrease the strike and or start voltage settings.
2.  Put the output control switch (on  the power source) in the
“Machine Control” position.
Jumper the “BYPASS” pins on
the voltage board.  Control the
arc voltage from the power
source.  If the problem is NOT
remedied the power source may
be at fault.  If the problem is
solved the NA-5 may be at fault.1.  The voltage board may be faulty. Replace.
1.  The voltage board may be faulty. Replace.
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							F-32TROUBLESHOOTING & REPAIRF-32
NA-5
Observe all Safety Guidelines detailed throughout this manual
If for any reason you do not understand the test procedures or are unabl\
e to perform the tests/repairs safely, contact the Lincoln Electric
Service Department for technical troubleshooting assistance before you p\
roceed. Call 216-383-2531 or 1-800-833-9353.
CAUTION
WELDING PROBLEMS
PROBLEMS
(SYMPTOMS)POSSIBLE AREAS OF
MISADJUSTMENTS(S)RECOMMENDED
COURSE OF ACTION
The arc is unstable or oscillating.1.  Check the welding cables for loose or faulty connections.
2.  Make sure the electrode and gas (if used) is correct for the process
being used.
3.  Put the output control switch (on the power source) in the
“Machine Control” position.
Jumper the “BYPASS “ pins on
the NA-5 voltage board.  Control
the arc voltage from the power
source.  If the problem is NOT
remedied the power source may
be at fault.  If the problem is
solved the NA-5 may be at fault.1.  The NA-5 voltage board may be faulty.  Replace.
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							F-33TROUBLESHOOTING & REPAIRF-33
NA-5
Observe all Safety Guidelines detailed throughout this manual
If for any reason you do not understand the test procedures or are unabl\
e to perform the tests/repairs safely, contact the Lincoln Electric
Service Department for technical troubleshooting assistance before you p\
roceed. Call 216-383-2531 or 1-800-833-9353.
CAUTION
FUNCTION PROBLEMS
PROBLEMS
(SYMPTOMS)POSSIBLE AREAS OF
MISADJUSTMENTS(S)RECOMMENDED
COURSE OF ACTION
The flux or gas/water solenoid does
not function (open).
The flux or gas/water solenoid con-
tinuously remains open. 1.  Make sure the switch on the flux hopper is in the ON position.
2.  Check light 7G located on the logic board.  This light should be
on when the flux valve would nor-
mally be active.  If light 7G does
not light the logic board may be
faulty.
1.  Check light 7G located on the logic board.  This light should be
lit only when the flux valve would
normally be active.  If light 7G is
lit continuously the logic board
may be faulty.
2.  Check to make sure the solenoid is not stuck in the open position.1. If light 7G, located on the logicboard, does light when the flux
(gas/water) solenoid is normally
active, check the CR1 relay.
Normal coil resistance is 10,000
ohms.  The contacts (terminals 2
and 4) should “close” when
110VDC is applied to the relay coil
(terminals 1 + and 3 -). 
2.  Check the wiring harness for loose or faulty connections
between the CR1 relay, the logic
board, the TS2 terminal strip and
the flux receptacle.  See wiring
diagram.
1.  Check the CR1 relay.  The con- tacts (terminal 2 and 4) should
“close” only when 110VDC is
applied to the relay coil. (termi-
nals 1+ and 3-).  If the contacts
are “closed” continuously replace
the CR1 relay.
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							F-34TROUBLESHOOTING & REPAIRF-34
NA-5
Observe all Safety Guidelines detailed throughout this manual
If for any reason you do not understand the test procedures or are unabl\
e to perform the tests/repairs safely, contact the Lincoln Electric
Service Department for technical troubleshooting assistance before you p\
roceed. Call 216-383-2531 or 1-800-833-9353.
CAUTION
WELDING PROBLEMS
PROBLEMS
(SYMPTOMS)POSSIBLE AREAS OF
MISADJUSTMENTS(S)RECOMMENDED
COURSE OF ACTION
The arc is unstable or oscillating.
The welding arc is variable or “hunt-
ing”.1.  Check the welding cables for loose or faulty connections.
2.  Make sure the electrode and gas (if used) is correct for the process
being used.
3.  Put the Lincoln power source in the machine control
mode.Jumper the “BYPASS” pins
on the NA-5 voltage board.
Adjust the weld voltage at the
power source for the process
being used.  If the problem is
NOT resolved the power source
may be faulty.
1.  Make sure the welding parame- ters are correct for the welding
procedure being used.
2.  Check the welding cables for- loose or faulty connections.
3.  Check the wire feeding path for restrictions.
4.  The contact tip may be worn. Check or replace.
5.  The welding power source may be faulty. Check or replace.1.  The NA-5 voltage board may be faulty Replace.
1. Put the Lincoln power source in the machine control mode.
Jumper the “BYPASS” pins on the
NA-5 voltage board.  Adjust the
weld voltage at the power source
for the process being used.  If the
problem is resolved check or
replace the control cable or the
NA-5 voltage board may be faulty.
2.  Perform the 
Wire Drive Motor
Test.
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							F-35TROUBLESHOOTING & REPAIRF-35
NA-5
Observe all Safety Guidelines detailed throughout this manual
If for any reason you do not understand the test procedures or are unabl\
e to perform the tests/repairs safely, contact the Lincoln Electric
Service Department for technical troubleshooting assistance before you p\
roceed. Call 216-383-2531 or 1-800-833-9353.
CAUTION
WELDING PROBLEMS
PROBLEMS
(SYMPTOMS)POSSIBLE AREAS OF
MISADJUSTMENTS(S)RECOMMENDED
COURSE OF ACTION
Poor arc striking with sticking or
“blast offs”.  The weld bead is ropey
and has porosity.1.  Make sure the welding parame- ters (voltages and wire feed
speed) and techniques are cor-
rect for the welding procedure
being used.
2.  Check the welding cables for loose or faulty connections.
3.  The contact tip may be worn. Check or replace.
4.  The welding power source may be faulty.  Check or replace.1. Put the Lincoln power source inthe machine control mode.
Jumper the “BYPASS” pins on the
NA-5 voltage board.  Adjust the
weld voltage at the power source
for the process being used.  If the
problem is resolved check or
replace the control cable or the
NA-5 voltage board may be faulty.
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							F-36TROUBLESHOOTING & REPAIRF-36
LED NumberFunctions Indicated By PC Board LEDS
1A +15VDC Analog Supply Present
1B-10VDC Analog Supply Present
1C Down Field Voltage Applied
1DUp Field Voltage Applied
1EArmature Voltage Applied
1F115VDC Relay Supply Present
7A +15VDC Logic Supply Present
7BStart Switch Pressed
7C Stop Switch Pressed
7DWelding Current Present
7ESignal to Apply Down Field Voltage
7G Signal to Operate Flux or Water Solenoid
7HSignal to Operate Travel Circuit
7JInch Down Switch Pressed
7K Signal to Operate Power Source Output Contactor
PC BOARD LED (LIGHT) DEFINITIONS
NA-5
LED LIGHT LOCATIONS
OI
LCG
LED 7B

LED 7C
LED 7D
LED7A

NA-5
LED 7J
LED 7K
LED 7G LED 7H
LED 7E
LED LIGHT LOCATIONS


NA-5POWER
LED 1FLED 1B
LED 1D
LED 1C LED 1E
LED 1A
Return to Section TOC
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							F-37TROUBLESHOOTING & REPAIRF-37
Light Location Idle Inch Up Inch Down Start  Stop Burnback Weld Arc
No. (PC Board) Mode Switch Switch Switch Switch Mode EstablishPressed Pressed Pressed Pressed
1A PowerON ON ON ON ON ON ON
1B PowerON ON ON ON ON ON ON
1C Power ON ONON
1D PowerON ON ON ON
1E PowerON ON ON ON
1F PowerON ON ON ON ON ON ON
7A LogicON ON ON ON ON ON ON
7B Logic ON*
7C Logic ON*
7D Logic ON ON
7E LogicON ONON
7G Logic ON* ONON
7H Logic ON**ON** ON
7J Logic ON*
7K Logic ON ON ON
PC BOARD LED (LIGHT) SEQUENCE TABLE ABOVE CODE 8300
NA-5
ON* only while switch is pressed                          ON** dependent\
 on travel mode
INDICATOR LIGHTS CONDITIONS FOR LIGHT ON Return to Section TOC
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