Lincoln Electric IM939 RED-D-ARC LN-25 PRO EXTREME - Manual (Page 30)

D-2 MAINTENANCE D-2
Wire Feed Speed Validation
(See Figure D.1)
Calibration of the LN25 PRO EXTREME may be required
when the p.c. board, wire feed speed potentiometer or
motor is replaced or serviced. Calibration matches the
scale on the name plate to the actual wire feed speed.
Tools required:
• RPM meter
• Constant voltage DC welding power source (DC-400,
V-350, CV-400 or equivalent)
• 7/16" open end wrench
To verify if calibration is necessary:
1. Turn power OFF.
2. Set the wire feed speed per the table.
Model gearing Wire Feed Speed Acceptable Range
Normal Speed
400 in/min 69 - 77 rpm
3. Remove the plastic cover from the lower portion of the
wire drive with a 7/16" wrench.
4. Connect the LN25 PRO EXTREME to the constant
voltage DC welding power source. The work lead of
the LN25 PRO EXTREME must be connected to the
work terminal of the power source.
5. Turn power ON.
6. Measure the motor rpm when the COLD FEED button
is pressed.
7. Verify the rpm is within the acceptable range.
To change the wire feed speed calibration:
(See Figure D.2)
Tools required:
• 5/16" nut driver
• RPM meter
• Shorting plug. The shorting plug shorts pins 1 & 5 of
connector J2 on the p.c. board. J2 is a 6 pin molex
connector.
1. Turn power OFF.
2. Remove the 4 screws holding the rear cover inside
the feeder and remove the cover.
3. Open the idle arm.
4. Set the wire feed speed per the table.
Model gearing Wire Feed Speed
Normal Speed
400 in/min
5. Connect the LN25 PRO EXTREME to the constant
voltage DC welding power source. The work lead of
the LN25 PRO EXTREME must be connected to the
work terminal of the power source.
6. Turn power ON.
7. Insert the shorting plug into connector J2 on the p.c.
board. The shorting plug shorts pins 1 & 5.
8. Remove the shorting plug.
9. Turn power OFF.
10. Replace the cover and secure with the screws.
LN-25 PRO EXTREME
COVER
MOTOR
SHAFT
FIGURE D.1 FIGURE D.2
COVER
P.C. BOARD