Spool Gun Control Test; Output Voltage Test; Wire Feed & Weld Test - Thermal Arc Fabricator 140 Service Manual

FABRICATOR 140, 180
E. Release the MIG gun switch. Reconnect the wire to
the temperature switch. Close the MIG gun switch and
observe the following:
1. Gas flows.
2. Feed roll turns slowly.
3. Output Voltage measures 21 VDC.
F. Release the MIG gun switch.
1. Gas flow stops.
2. Feed roll stops turning.
3. Output Voltage reading slowly decreases to 0 VDC.
G. Connect a DC Voltmeter to the two wires connected
to the Wire Feed Motor (M2). Close the MIG gun switch
and vary the WIRE SPEED CONTROL Potentiometer
from minimum "0" to maximum (10) setting.
1. Feed roll speed will increase with potentiometer
increase.
2. Motor voltage should vary from approximately 2
VDC to 19VDC.
This completes the Logic & Control Test. If the above
steps were correct, proceed to the next section, Spool
Gun Control Test. If the unit does not function as detailed
above, note the symptom and proceed to Section 6.09
Logic & Control Problems.

6.05 Spool Gun Control Test

A. Remove the MIG gun plug P6 from receptacle J6.
Install a jumper between J6-2 and J6-5.
1. Gas flows.
2. Wire Feed Motor does not turn.
B. Set WIRE SPEED CONTROL potentiometer to "0"
position. Measure the voltage between J6-1 to J6-3
while adjusting the WIRE SPEED CONTROL
potentiometer from minimum to maximum setting.
1. Voltage should vary from approximately 4 VDC
to 20 VDC.
C. Remove the jumper and the meter from J6 and re-
install MIG gun plug P6.
This completes the Spool Gun Control Test. If the above
steps were correct, proceed to the next section, Output
Voltage Test. If the unit does not function as detailed
above, check the wire harness connections from the PCB
to J6.
Manual 0-4992
ADVANCED TROUBLESHOOTING

6.06 Output Voltage Test

A. Connect a voltmeter to the Positive and Negative
Polarity Change Over terminals. Close the MIG gun
switch and record the voltage displayed.
1. Repeat the check for each of the VOLTAGE
CONTROL SWITCH settings. The voltages should
measure approximately as outlined in the
following charts:
FABRICATOR 140
Voltage Control Switch SW1 Setting
1
2
3
4
FABRICATOR 180
Voltage Control Switch SW1 Setting
1
2
3
4
5
6
This completes the Output Voltage Test. If the above steps
were correct, proceed to the next section, Wire Feed &
Weld Test. If the unit does not function as detailed above,
note the symptom and proceed to Section 6.12 T1
Transformer Test.
6.07 Wire Feed & Weld Test
A. Reconnect the wires to the Polarity Change Over
terminals for Reverse Polarity (GAS). Close the
PRESSURE ADJUST DEVICE.
B. Position the gun for welding and close the MIG gun
switch.
1. Gas Flows.
2. Wire feeds out.
3. Welding arc established.
This completes the Wire Feed & Weld Test. If the above
steps were correct, the system is functioning properly. If
the unit does not function as detailed above, note the
symptom and proceed to Section 6.10 Wire Feed and Weld
Problems.
6-2
Voltage
21
24
28
34
Voltage
21
23
26
30
35
41
January 25, 2008