Locate the tach leads on plug j4. see, Figure f.5, Troubleshooting and repair – Lincoln Electric POWER MIG SVM157-A User Manual

Page 52: Warning

TROUBLESHOOTING AND REPAIR

F-18

POWER MIG 200

WIRE DRIVE MOTOR AND TACHOMETER FEEDBACK TEST

(continued)

TEST FOR FEEDBACK VOLTAGE
TO CONTROL BOARD

1. Disconnect the main AC input power to

the machine.

2. Locate plug J4 and the tach leads.

See Figure F.5.

3. Connect main input power to the

machine.

4. Make the following voltage tests:

a. Turn the machine OFF between

each test.

b. Carefully insert the meter probes

into the lead side of plug J4. See
Figure F5.

c. Turn the machine ON and pull the

gun trigger to conduct the voltage
test.

5. If the 3.0 to 4.0 VDC is present, the

tachometer circuit is sending the correct
feedback signal to the control PC board.
Check the leads and plug J5. See the
Wiring Diagram.

6. If the 3.0 to 4.0 VDC is NOT present

or NOT correct, the control PC board
is not receiving the proper feedback
voltage from the tachometer circuit.

7. If the leads are okay, the tachometer

circuit may be faulty, replace the
tachometer circuit.

8. Replace the tool tray.

FROM LEAD

TO LEAD

EXPECTED

VOLTAGE

Black (-)

BLUE (+)

3.0 TO 4.0

VDC

ELECTRIC SHOCK can kill.

• Do not touch electrically live

parts such as output terminals
or internal wiring.

• All input power must be electri-

cally disconnected before pro-
ceeding.

WARNING

Black
Tach

J11

Black
Arm

White
Arm

Blue
Tach

Red
Tach

FIGURE F.5. – PLUG J4