Lincoln Electric SVM157-A service manual Test for Feedback Voltage to Control Board, Vdc

Models: SVM157-A

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TOC

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F-18

TROUBLESHOOTING AND REPAIR

F-18

WIRE DRIVE MOTOR AND TACHOMETER FEEDBACK TEST

(continued)

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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.

c. Turn the machine ON and pull the gun trigger to conduct the voltage test.

FROM LEAD

TO LEAD

EXPECTED

 

 

VOLTAGE

Black (-)

BLUE (+)

3.0 TO 4.0

 

 

VDC

 

 

 

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3.Connect main input power to the machine.

4.Make the following voltage tests:

WARNING

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.

a.Turn the machine OFF between each test.

b.Carefully insert the meter probes into the lead side of plug J4. See Figure F5.

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.

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FIGURE F.5. – PLUG J4

Black

 

Black

White

Tach

 

 

Arm

 

 

 

 

 

 

 

 

 

 

 

 

Arm

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

J11

Red Blue

Tach Tach

POWER MIG 200

Page 52
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Lincoln Electric SVM157-A service manual Test for Feedback Voltage to Control Board, Vdc