Lincoln Electric RANGER 305G EFI Service Manual page 59

LINCOLN ELECTRIC
15. Locate plugs J3 and J6 on the weld control board. See Figure F.17. See Wiring Diagram. Reconnect
the plugs and check for dirt, corrosion, damaged, expanded or incorrectly positioned terminals.
Repair or replace wiring components as needed and reconnect the plugs to the weld control board.
16. Restart the machine and apply a 200 amp load across the weld terminals. If the machine will not
produce 200 amps of current, apply as much load as you can.
17. Using the voltmeter, measure and note the DC voltage at the weld output terminals. See Wiring
Diagram.
18. Check the voltage between leads 204S+ (J6-1) and lead 208B- (J3-15) at the weld control board
plugs. See Figures F.17 and F.18. See Wiring Diagram. The voltage should be the same as was
measured at the weld terminals.
19. If the voltage readings are different, check the wiring and connections between the welding
terminals and the weld control board. See Wiring Diagram.
20. Connect the millivolt meter probes between lead 206S+ (J6-2) and lead 204S- (J6-1) on the weld
control board. See Figures F.17 and F.18. See Wiring Diagram. If the machine is currently
producing 200 amps the millivolt meter should read about 25 millivolts.
21. If the machine cannot produce 200 amps of weld current, the correct millivolt signal will need to be
calculated by dividing the reading displayed on the external ammeter by 8. See the following
explanation.
22. The shunt used in this machine will produce 50 millivolts at a load of 400 amps or 8 amps per
millivolt.
23. To calculate the correct millivolt signal for a given load, you divide the number of amps displayed on
the ammeter by 8. Example: If your ammeter reads 75, (75/8 = 9.4) if the shunt is working correctly
and the wiring between the shunt and the weld control board is in good condition, the meter
connected at the weld control board should be reading about 9.4 millivolts.
24. If the millivolt reading is incorrect, check the wiring between the shunt and the weld control board
for damage, grounds and faulty connections. If the wiring is good, the shunt and lead assembly is
faulty and should be replaced.
25. Perform the Case Cover Replacement Procedure.
Ranger® 305G EFI Service Manual
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