Lincoln Electric IM 513-B manual Procedure for Checking the Capacitor Bank Contactor CR3

3.Check to see that leads 2 and 4 are con- nected. Put a voltmeter across these leads and the meter should read close to zero volts. If voltage reads approximately 15 volts, then the trigger circuit (leads 2-4) is open. Check the wiring from the WFM control box to the WFM control panel for loose or broken connections. Turn machine off and check the operation of the “LOCAL/REMOTE” switch by connect- ing an ohmmeter across leads 2 and 4 at the switch with switch positioned in “LOCAL” mode, if resistance is high or open replace the switch.

4.Check for coil voltage across leads 633 and 634 at P2 plug to the P.C. Board. If voltage is present, check for loose or bro- ken leads from the plug to the contactor coil. If connections are good and voltage correct, replace contactor CR4.

5.If no voltage is present at CR4 contactor coil, see Procedure for Replacing P.C. Boards.

E.Procedure for Checking the Capacitor Bank Contactor (CR3)

1.Verify machine is in CV (wire) mode. Measure voltage across leads 630 and 631 at the contactor. The voltage should be approximately 120 +/- 15V DC with engine set on high idle. If voltage is not present, go to step 3 of this procedure.

2.If the proper voltage is present at leads 630 - 631, measure the voltage between L2 terminal and terminal opposite L2. If the voltage is equal to the output voltage across the positive and negative output terminals, replace the contactor CR3.

3.If the proper voltage is not present at leads 630 - 631, check the wiring to CR3 coil for loose or broken connections. If connections are good, see Procedure for Replacing P.C. Boards.

3.Disconnect P.C. Board harness plug P2 from the P.C. Board.

4.With an ohmmeter on X1K, connect it to lead 76A and 77A on S2. Rotate the volt- age control potentiometer. The resistance reading should be from approximately zero to 10K ohms. Check the resistance reading between lead 75 on potentiometer and 77A on switch S2. The reading must be 10K ohms. No reading will indicate an open potentiometer and a low reading will indicate a shorted or partially shorted potentiometer; in either case, replace. Reconnect P.C. Board plug P2.

G.Remote Control Check

1.The remote control connector pin assign- ments are: pin G-75A, pin F-76B, pin E- 77B. Make sure remote control connec- tions are tight and check for any physical damage to the control cable. Connect an ohmmeter across lead 75 and 76B on switch S2. With S2 in remote mode, rotate the potentiometer in the remote control. The resistance reading should vary from zero to 10K ohms. Repeat with ohmmeter across 77B and 76B with the same results. Connect an ohmmeter across 75 and 77B. The reading should be 10K ohms. If an open or short is mea- sured replace the potentiometer.

F.Checking Voltage Control Potentiometer on Machine

1.Turn machine off.

2.Remove the control panel screws and open the front cover. Turn the “LOCAL/REMOTE” switch (S2) to “REMOTE”.

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