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b-20
MAKING A WELD
1. Inch the electrode through the gun and cable and
then cut the electrode within approximately 3/8" of
the end of the contact tip for solid wire and within
approximately 3/4" of the extension guide for cored
wire.
2. Connect the work cable to the metal to be welded.
The work cable must make good electrical contact
to the work. The work must also be grounded as
stated in the Safety section at the beginning of this
manual.
3. Be sure the welding power source and the shield-
ing gas supply are turned on.
4. Position the electrode over the joint. The end of
the electrode should be slightly over the joint.
5. Lower the welding helmet, close the gun trigger
and begin welding. Hold the gun so that the con-
tact tip to weld distance gives the correct electrical
stickout as required for the procedure being used.
6. To stop welding, release the gun trigger and then
pull the gun away from the work after the arc goes
out.
PROCEDURE AT END OF COIL
When the wire on the reel is used up, follow this pro-
cedure for removing the old wire from the conductor
cable and loading a new reel.
1. Cut the end of the electrode off at the gun end. Do
not break it off by hand since this puts a slight bend
in the wire and makes it difficult or impossible to
pull it back through the nozzle.
2. Uncouple the gun conductor cable from the wire
drive unit.
3. Lay the cable out straight.
4. Using pliers to grip the wire, pull it out of the cable
from the connector end. Do not pull it from the gun
end.
5. Put the conductor cable back on the wire drive unit
after the electrode has been removed.
6. Load a new reel of wire and feed it through the
cable as described earlier in this section.
OPERATION
SECURITY OF WELD PROCEDURE
SETTINGS
There are two ways to prevent or limit unauthorized
readjustment of the LN-9 GMA voltage and wire feed
speed controls.
1. Once the procedure is set, the security panel of the
2. The control range of the procedure control knobs
NOTE: Steps g) through i) will have to be repeated if
LN-9 GMA and LN-9F GMA Wire Feeder
LN-9 GMA can be locked to prevent access to the
control knobs.
can be limited to either about 3% or about 15% of
the full range control by installing a knob rotation
stop screw to either or both of the control knobs.
This stop screw is installed in the following man-
ner:
a) Turn off the input power to the LN-9 GMA unit.
b) Loosen the knob set screw and remove the
control knob and the felt seal located behind
the knob.
c) Remove the control potentiometer locknut and
fiber spacer, then open the control panel and
remove the potentiometer from the panel.
d) Install a 1/2" long, pan or round head, #4 sheet
metal screw into the 0.10" dia. hole located
.40" from the center of the potentiometer hole
so that the head is on the back side of the
panel (inside the control box).
e) Remount the control potentiometer with the
fiber spacer under the locknut, then close and
secure the control panel.
f)
Replace the felt seal around the fiber spacer
so that the #4 screw protrudes between the
fiber spacer and the felt seal.
g) Turn on the input power to the LN-9 GMA unit
and set the desired procedure by rotating the
potentiometer shaft.
h) Carefully replace the control knob so that the
#4 screw inserts into the center of the shorter
length channel on the back of the knob for
about 3% of the total range of control, or the
center of the longer length channel for about
15% of the total range of control.
i)
With finger pressure on the knob against the
felt seal, carefully retighten the knob set screw.
you want to change the set procedure to a
value outside the selected 3% or 15% control
range limit.
b-20
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Troubleshooting
