Lincoln Electric POWER MIG SVM167-A Service Manual page 53

F-17
TROUBLESHOOTING AND REPAIR
WIRE DRIVE MOTOR AND WIRE SPEED POTENTIOMETER TEST
TEST FOR FEEDBACK VOLTAGE
TO CONTROL BOARD
1. Disconnect the main AC input power to
the machine.
2. Locate plug J1 and the potentiometer
leads. See Figure F.5. #1113A and
1109A.
3. Connect main input power to the
machine.
ELECTRIC SHOCK can kill.
• Do not touch electrically live
• All input power must be electri-
4. Make the following voltage tests:
a. Turn the machine OFF between
each test.
1
9
(continued)
WARNING
parts such as output terminals
or internal wiring.
cally disconnected before pro-
ceeding.
FIGURE F.5. – PLUG J1
1109A
POWER MIG® 215
b. Carefully insert the meter probes
into the lead side of plug J1. See
Figure F5.
c. Turn the machine ON and pull the
gun trigger to conduct the voltage
test.
FROM LEAD TO LEAD
1109 A 1113 A
5. If the 0 to 5 VDC is present, the
potentiometer circuit is sending the
correct feedback signal to the control
PC board. Check the leads and plug
J1. See the Wiring Diagram.
6. If the 0 to 5 VDC is NOT present or
NOT correct, the control PC board is
not receiving the proper feedback voltage
from the potentiometer circuit.
7. If the leads are okay, the potentiometer
circuit may be faulty, replace the
potentiometer circuit.
8. Replace the tool tray.
1103A
1113A
F-17
EXPECTED
VOLTAGE
0 - 5 VDC
8
16