To Start The Welder; Feeding Wire Electrode; Idle Roll Pressure Setting; Wire Drive Configuration - Lincoln Electric POWER MIG SVM170-A Service Manual

B-6

TO START THE WELDER

Turn the Power Switch switch to ON. This lights the red
LED display lights. With the desired voltage and wire
speed selected, operate the gun trigger for welder out-
put and to energize the wire feed motor.

FEEDING WIRE ELECTRODE

WARNING
When triggering, the electrode and drive mecha-
nism are electrically "hot" relative to work and
ground and remain "hot" several seconds after the
gun trigger is released.
------------------------------------------------------------------------
NOTE: Check that drive rolls, guide plates, and gun
parts are proper for the wire size and type being used.
Refer to Table C.1 in Accessories section.
1. Turn the Readi-Reel or spool until the free end of
the electrode is accessible.
2. While securely holding the electrode, cut off the
bent end and straighten the first six inches. (If the
electrode is not properly straightened, it may not
feed properly through the wire drive system.)
3. Release the pressure on the idle roll by swinging
the adjustable pressure arm down toward the
back of the machine. Lift the cast idle roll assem-
bly and allow it to sit in an upright position. Leave
the outer wire guide plate installed. Manually feed
the wire through the incoming guide bushing and
through the guide plates (over the drive roll
groove). Push a sufficient wire length to assure
that the wire has fed into the gun and cable
assembly without restriction. Reposition the
adjustable pressure arm to its original position to
apply pressure to the wire.
4. Press gun trigger to feed the electrode wire
through the gun.

IDLE ROLL PRESSURE SETTING

WARNING
ELECTRIC SHOCK can kill.
• Turn the input power OFF at the welding
power source before installation or
changing drive rolls and/or guides.
• Do not touch electrically live parts.
• When inching with the gun trigger, electrode and
drive mechanism are "hot" to work and ground
and could remain energized several seconds
after the gun trigger is released.
• Only qualified personnel should perform mainte-
nance work.
OPERATION
The pressure arm controls the amount of force the drive
rolls exert on the wire. Proper adjustment of both pressure
arm gives the best welding performance. For best results,
set both pressure arms to the same value.
Set the pressure arm as follows (See
Figure B.3):
Aluminum wires
Cored wires
Steel, Stainless wires
CORED WIRES
OUTERSHIELD
METALSHIELD
INNERS HIELD

WIRE DRIVE CONFIGURATION

(See Figure B.4)
Changing the Gun Receiver Bushing
ELECTRIC SHOCK can kill.
• Turn the input power OFF at the welding power
source before installation or changing drive rolls
and/or guides.
• Do not touch electrically live parts.
•• When inching with the gun trigger, electrode and
drive mechanism are "hot" to work and ground
and could remain energized several seconds
after the gun trigger is released.
•• Only qualified personnel should perform mainte-
nance work.
------------------------------------------------------------------------
Tools required:
• 1/4" hex key wrench.
Note: Some gun bushings do not require the use of
the thumb screw.
1. Turn power off at the welding power source.
2. Remove the welding wire from the wire drive.
3. Remove the thumb screw from the wire drive.
4. Remove the welding gun from the wire drive.
POWER MIG 255C
between 1 and 3
between 3 and 4
between 4 and 6
FIGURE B.3
SOLID WIRES
1
3 2
ALUMINUM
4
STEEL
5
STAINLE SS
6
B-6