Thermal Arc 281 FABRICATOR, Service Manual

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FABRICATOR 281
ADVANCED TROUBLESHOOTING -8 Manual No. 0-4880B
3. Defective or faulty connection on Umbilical
Cable.
a. Measure between JB-7 to JB-9 for approx
15VDC. If voltage is not correct, then check
connections to J1 on Power Supply to A2281
Terminal Block.
4. Faulty MAIN PCB
a. With gun switch closed, measure voltage be-
tween JB-6(-) to JB-8 (+) for approx 10 VDC.
If voltage is 0 VDC, replace Control PCB.
5. Defective PCB 3
a. With Gun switch closed and WIRE FEED
SPEED set to "4" , measure voltage between
JB-8 on the MAIN PCB to X1-3 on PCB 3 for
approximately 12VDC . If voltage is not pres-
ent, replace PCB 3.
F. When Gun Switch is closed, gas flows, contactor
closes, display shows 0 volts, and feed roll does
not turn.
1. Defective Contactor W1
a. With Gun Switch closed, measure for 230VAC
at the contactor between terminals T1 to T3.
If voltage is low or not present, replace W1.
2. Defective FINE or COARSE VOLTAGE CONTROL
SWITCH
a. See VOLTAGE CONTROL SWITCH test
procedure, page 7-11.
3. Defective Rectifier assembly
a) Check per the diode test procedure page 7-13.
4. Defective Main transformer
a) Check main transformer per test procedure
page 7-14.
G. When Gun Switch is closed, gas flows, contactor
closes, feed roll turns, but display shows 0 volts.
1. Open wire between shunt and PCB4.
a. Measure voltage between X1-5 to X1-6
for 15VDC. If voltage is not correct, check
continuity of wire #22 Violet & # 21 Orange.
2. PCB 4 is defective.
a. Measure voltage between X1-3 to X1-1 for
32VAC. If voltage is correct, replace PCB4.
7.10 Spool Gun Control (J1) Problem
A. Gas does not flow when jumper is connected
between J11 Pins D & G
1. Gas supply not connected or turned on
a. Verify gas supply to unit is correct and con-
nected to the gas inlet labeled:
2. Defective gas solenoid SOL2
a. Measure for 32VAC at SOL2 between Orange
wires (# 31A & 31B) and Red wire (#60). If
voltage is correct replace SOL2.
3. Defective PCB3
a. Measure voltage between X3-5 to X3-4
on PCB3 for 0VAC. If voltage not correct,
replace PCB3.
B. Voltages to J1 are not correct when jumper is
installed between pins D & G
1. Defective PCB 3
a. Measure voltage between X3-3 to X3-4 for
0VDC when jumper is installed between J1-
D & G. If voltage is correct, replace PCB 3.
7.11 Output Voltage Problem
A. Output is low in one or more OUTPUT VOLTAGE
CONTROL SWITCH positions
1. Defective OUTPUT VOLTAGE SELECTION
SWITCH
a. Check continuity of switch. See test
procedure page 7-11.
2. Defective MAIN TRANSFORMER
a. Check Main transformer per test procedure
on page 7-14.