
D-2
MAINTENANCE
D-2
NA-3 AND NA-4
CONTROL BOX
GENERAL
Inspect the control box every 3 months. If
needed, blow dirt out using
low pressure air.
No further maintenance should be required.
CIRCUIT PROTECTION
The circuit breaker mounted on the left side
of the control box protects the control circuit
from short circuit conditions and from severe
wire feed overloads. If it is open, determine
and correct the cause for the overload. To
reset the circuit breaker, push in the red
button shown in Figure D.1.
FIGURE D.1 – CIRCUIT BREAKER
RESET BUTTON.
The field circuit fuse, shown in Figure D.2, is
a 1/2 amp, slo-blo fuse. It is located on the
control PC board and protects the field circuit.
The following conditions could cause this field
circuit fuse to open:
FIGURE D.2 – CONTROL BOARD FUSE
AND LED LOCATIONS.
1. Complete or partial wire feed motor field
short. Normal field resistance is
approximately 700 ohms.
2. A welding procedure with a lot of
electrode-to-puddle shorting. This
rapid arc shorting may cause the field
voltage polarity to change frequently
and blow the fuse. (Indicator LEDs 1C
and 1D will
both flicker when welding.)
3. Too low of an impedance when idle
across terminals #21 to #67. Condition
may be caused by the following:
a. Something external to the NA
controls and power source
causing a partial short across
terminals #21 to #67.
b. Use of a non-Lincoln Electric
power source.
c. A defective Lincoln Electric power
source.
4. A defective control board.
The control PC board is located behind the
inner panel door.
CIRCUIT
BREAKER
RESET
BUTTON
1/2 AMP
1/3 AMP
1/3
AMP
POWER
SUPPLY
FUSE
REMOTE
SWITCHES
FUSE
(NEWER
MODELS)
FIELD
CIRCUIT
FUSE
INDICATOR
LED'S
1D 1C
Summary of Contents for NA-3S
Page 6: ...NOTES v v NA 3 AND NA 4 ...
Page 47: ...NOTES B 18 B 18 NA 3 AND NA 4 ...
Page 53: ...NOTES C 6 C 6 NA 3 AND NA 4 ...
Page 91: ...NOTES F 26 F 26 NA 3 AND NA 4 ...
Page 101: ...NOTES NA 3 AND NA 4 ...