Testing For A Shorted Nozzle; Replace A Gun Liner - Craftsman 196.205040 Manual Del Usuario

Failure to keep the nozzle adequately
cleaned can result in the following
problems:
A SHORTED nozzle results when spatter
buildup bridges the insulation in the nozzle,
allowing welding current to flow through it as
well as the contact tip. When shorted, a
nozzle will steal welding current from the
wire whenever it contacts the grounded work
piece. This causes erratic welds and reduced
penetration. In addition, a shorted nozzle
overheats the end of the gun, which can
DAMAGE the front-end of the gun.
A RESTRICTED nozzle is created when
enough slag builds up in the nozzle to affect
the direction, concentration, and/or rate of
the shielding gas flow. This problem can
cause porous, brittle welds and reduce
penetration.

TESTING FOR A SHORTED NOZZLE

Arcing between the nozzle and the work
piece ALWAYS means the nozzle is shorted,
but this can be hard to detect through the
lens of a welding helmet. The following
testing method is another way to tell if a
nozzle is shorted.
With the welder unplugged from the ac
power source, touch the probes of an
ohmmeter or continuity tester to the end of
the contact tip and the outside of the nozzle.
If there is any continuity at all, the nozzle IS
shorted. Clean or replace as needed.

REPLACE A GUN LINER

When installing a new gun liner, care must be
taken not to kink or otherwise damage the gun
liner. See Figure 21 for the drive assembly and
Figure 22 for the gun assembly.
1. Turn OFF welder POWER SWITCH and
unplug welder from power supply.
2. Open the welder side panel.
3. Lower Drive Tension Adjustment knob
and lift the Drive Tension Arm up off the
drive roller.
4. Turn the wire spool counter-clockwise (be
sure to hold onto the wire itself while
turning the spool or the wire will unspool
itself when it becomes free of the gun
liner), and remove wire from gun
assembly.
5. Lay gun cable and gun handle straight
out in front of unit.
24
6. Unscrew large flat head screws which
hold handle to welder cabinet and
remove handle.
7. Remove self tapping screws which con-
nect welder cabinet to frame and lift cabi-
net away from welder.
8. Remove Cable Holding Clamp according
to the following steps:
a) Remove the two self tapping screws at
the end of Cable Holding Clamp clos-
est to the Drive Roller.
b) Remove the two bolts at the end of
Cable Holding Clamp closest to Gun
Cable. Note: There are two nuts on
opposite side of dividing panel which
hold the bolts in place.
9. Take gun handle halves apart by remov-
ing the five phillips head screws.
10. Remove gas hose from fast coupler fit-
ting on Gas Valve. Depress lip on fast
coupler fitting back towards fitting and
pull gas hose out.
11. Remove Fast Coupler Fitting from Gas
Valve using a 9 millimeter wrench.
12. Firmly hold the brass fitting on the end of
the gun liner with a wrench and rotate
Gas Valve counterclockwise to unscrew
fitting.
Note: Rotate Gas Valve - Do not rotate
brass fitting or gun liner will twist inside
gun cable and may cause damage to gun
cable.
13. The Live Wire Terminal is held in place
on the Gas Valve by the brass fitting on
the end of the gun liner. When the brass
fitting is removed, slide the Live Wire
Terminal off of the brass fitting.
14. Firmly grip the gun cable and pull the gun
liner all the way out.
15. Install the new gun liner into gun cable,
starting from the end where the welding
gun will be mounted, and feeding the
liner all the way through the gun cable to
the wire feed roller.
Note: It may be helpful to apply a small
amount of liquid soap to the end of the
gun liner to decrease resistance during
installation process.
16. Slide the eyelet of the Live Wire Terminal
onto the threaded end of the gun liner
brass fitting.