Lincoln Na5 Service Manual

F-68TROUBLESHOOTING & REPAIRF-68
9.  Locate the speedmeter PC board.See Figure F.10
10.  Apply input power to the NA-5.
11.  Test for AC supply to the speed-
meter PC board.
• Check for 8 to 11VAC from lead #601 ot #602.  See Figure F.10
Note: The coating will have to be
removed from the test points to ensure
accurate voltmeter readings.  If the cor-
rect AC voltage is not present check for
loose or faulty connects with the associ-
ated leads.  See wiring diagram. 12.  
Test for DC volts on the speed-...

F-69TROUBLESHOOTING & REPAIRF-69
13. Test Speedmeter Digital Meter
Accuracy
• Use a test meter with at least 3- 1/2 digits and +/- 0.5% accuracy.
• Connect the + probe to TP4 and the - probe to lead 510P.  Do NOT
disconnect plug.
Note:  The coating will have to be
removed from the test points to ensure
accurate meter readings. • With the NA-5  speedmeter read-ing SET values of STRIKE speed,
adjust the strike wire speed con-
trol until the test meter matches
the settings in the table below.
• If the NA-5...

F-70TROUBLESHOOTING & REPAIRF-70
14. Test Speedmeter PC Board
Accuracy
• Use a test meter with at least 3- 1/2 digits and +/- 0.5% accuracy.
• Connect the + probe to lead #519 (Jumper lead)  and the - probe to
lead #510P.  Do not  discon-
nect plug.
Note: The coating will have to be
removed from the test points to ensure
accurate meter readings. • With the NA-5  speedmeter read-ing SET values of STRIKE speed ,
adjust the strike wire speed con-
trol until the NA-5 speedmeter
matches the settings in the...

F-71TROUBLESHOOTING & REPAIRF-71
NA-5
PC BOARD(S) REMOVAL AND REPLACEMENT
DESCRIPTION
The following procedure will aid the technician in removing and replacin\
g the printed circuit
boards for maintenance or replacement.
MATERIALS NEEDED
Phillips head screwdriver
5/16 Nutdriver
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...

F-72TROUBLESHOOTING & REPAIRF-72
PROCEDURE
Before starting the following procedure,
refer to the 
PC Board
Troubleshooting Procedures 
at the
beginning of this section.
1.  Remove the input power to the NA- 5.
2.  Using the 5/16  nutdriver open the control box PC board cover.
3.  Carefully remove the molex type plugs (and leads) connected to the
PC board that is to be removed.
4.  Using the phillips head screwdriver, remove the PC board mounting
screws.
5.  Carefully remove the PC board.
REPLACEMENT...

F-73TROUBLESHOOTING & REPAIRF-73
NA-5
DIGITAL METER AND METER PC BOARD REMOVAL AND REPLACEMENTDESCRIPTION
The following procedure will help the technician remove the digital mete\
rs and meter PC
boards for repair or replacement.
MATERIALS NEEDED
5/16 Nutdriver
Phillips head screwdriver
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-74TROUBLESHOOTING & REPAIRF-74
METER PC BOARD REMOVAL
PROCEDURE
1.  Remove input power to the NA-5.
2.  Using the 5/16 nutdriver open thecontrol box PC board access door.
3.  Locate and unplug the meter PC board that is to be removed.  See
Figure F.11
4.  Using the 5/16 nutdriver remove the four PC board mounting nuts.  See
Figure F.11 5.  Carefully remove the meter PC
board. 
Note insulation placement for reassem-
bly. Also make sure the plug on the
back of the PC board plugs into the
prongs on the...

F-75TROUBLESHOOTING & REPAIRF-75
DIGITAL METER REMOVAL
PROCEDURE
1.  Using the phillips head screwdriverremove the four screws from the
meter bezel.  See Figure F.12
2.  Carefully remove the bezel assem- bly.
3.  Carefully remove the meter shield assembly. 4.  Using the 5/16 nutdriver, remove
the two nuts, screws and lockwash-
ers holding the digital meter to the
cover assembly.
5.  Carefully remove the digital meter.
DIGITAL METER AND METER PC BOARD REMOVAL AND REPLACEMENT
NA-5
FIGURE F.12 METER BEZEL...

F-76TROUBLESHOOTING & REPAIRF-76
REPLACEMENT PROCEDURE
1.  With the 5/16 nutdriver, fasten thedigital meter to the cover assembly
with two screws, nuts and lockwash-
ers. 
2.  Using the phillips head screwdriver, reattach the meter shield and bezel
assembly.
3.  Position the insulation and plug the PC meter board into the digital
meter.
4.  Mount the meter PC board using the four nuts previously removed.
5.  Reattach the molex plug.
6.  Close and secure the access door.
DIGITAL METER AND METER PC BOARD...

F-77TROUBLESHOOTING & REPAIRF-77
NA-5
TACH PC BOARD REMOVAL AND REPLACEMENT
DESCRIPTION
The following procedure will help the technician remove the Tach PC boar\
d and related com-
ponents for repair or replacement.
MATERIALS NEEDED
5/16 Nutdriver
Slot head screwdriver
Phillips head screwdriver
3/8 Wrench
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...