LN-25
D-1
ELECTRIC SHOCK can kill.
• Do not operate with covers
removed.
• Turn off power source before
installing or servicing.
• Do not touch electrically hot
parts.
• Turn the input power to the
welding power source off at
the fuse box before working
in the terminal strip.
• Only qualified personnel
should install, use or ser-
vice this equipment.
CIRCUIT PROTECTION AND
AUTOMATIC SHUTDOWN
CONTROL PC BOARD FUSE
On G1757-6 (or higher part no.) P.C. Boards the
1
⁄
8
amp fuse was replaced with electronic protection for
trigger circuit faults to electrode circuit.
On G1757-2 through -5 part no. PC boards, the
1
⁄
8
amp fuse interrupts the 500A lead to the trigger
switch. On G1757- 1 PC boards a 5 amp fuse was
used to interrupt the 667 lead. The LN-25 will not
operate if the fuse is blown.
AUTOMATIC PROTECTION SHUTDOWN
(See Automatic Protection Shutdown Section.)
ADJUSTING SPEED
SENSOR MODULE
The LN-25 Speed Sensor Module is a three lead Hall
Effect switch device encased in an externally
threaded housing which is screwed into a mounting
plate on the motor side of the wire drive gearbox.
Proper positioning of this module is critical to proper
operation of the LN-25 wire feed speed control. If the
ROUTINE MAINTENANCE
DRIVE ROLLS AND GUIDE TUBES
After feeding every coil of wire, inspect the drive roll
section. Clean it as necessary. Do not use a solvent
for cleaning the idle roll because it may wash the
lubricant out of the bearing. The drive roll, idle roll
and guide tubes are stamped with the wire sizes they
will feed. If a wire size other than that stamped on
the rolls is to be used, the rolls and guide tubes must
be changed.
The drive rolls for .035 through .052 cored electrode
and
1
⁄
16
through
5
⁄
64
electrode have a double set of
teeth so they can be reversed for additional life.
Drive rolls for .023 through .052 solid electrode and
aluminum sizes have no teeth but use two grooves
so they also can be reversed for additional life.
See Wire Feed Drive Roll and Guide Tube Kits Sec-
tion for roll changing instructions.
WIRE REEL SPINDLE
No routine maintenance required. Do not lubri-
cate spindle.
WARNING
SAFETY PRECAUTIONS
CONTROL BOX
Every six months open and inspect the control sec-
tion. The accumulated dirt should be gently blown off
all of the electrical components. Be sure the air that
is being used is dry. Check that lead plugs are secure
in their receptacles.
WIRE DRIVE MOTOR AND GEAR BOX
Every year examine the gear box. Paint the gear
teeth with molydisulfide filled grease. Lincoln
specification E2322.
Do not
use a graphite grease.
Check the motor brushes. Replace if they are worn
down to
1
⁄
4
’’ or less. When ordering feed motor
b r u s h e s , g i v e a l l i n f o r m a t i o n f r o m t h e motor
nameplate.
GUN AND CABLE MAINTENANCE
See IM manual provided with the gun and cable
assembly.
MAINTENANCE
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