COMPONENT LOCATION AND
ACCESS
CONTROL PC BOARD
Remove the left case side. Use a 3/8" Nut Driver or
other suitable tool.
NOTE: The Case side can be removed while roof is in
place, as long as the three screws which secure the
roof to the case side are removed. The PC Board is
mounted on left divider assembly and can be removed
with a phillips head screwdriver.
DISPLAY PC BOARD, ARC
STARTER/BYPASS PC BOARD
Remove the roof and both case sides. Use a 3/8" Nut
Driver or other suitable tool. These PC Boards are
located on the inside case front of the machine.
SPARK GAP ASSEMBLY, HIGH VOLTAGE
TRANSFORMER
Remove the right case side. Use a 3/8" Nut Driver or
other suitable tool. The high voltage transformer is
mounted to the base. The spark gap assembly is locat-
ed on the inside case front.
MAIN RECTIFIER
Remove the roof and both case sides. Next, remove
the case back assembly. Use a 3/8" Nut Driver or other
suitable tool. The main rectifier is mounted to the main
transformer, in front of the cooling fan.
SPARK GAP ADJUSTMENT
The spark gap is set at the factory to a gap of 0.015
inches (0.4 mm). This setting is adequate for most
applications. Where less high frequency is desired, the
setting can be reduced to 0.008 inches (0.2 mm).
To adjust the spark, first be sure that the input power to
the machine is ‘OFF’ AT THE DISCONNECT SWITCH
OR FUSE BOX. The high voltages developed in the
high frequency circuit can be lethal. Next, remove the
right case side. Use a 3/8" Nut Driver or other suitable
tool. Check the spark gap spacing with a feeler gauge.
If adjustment is required, pull off one of the two leads
going to the aluminum spark gap blocks. Adjust the
gap by loosening the Allen head screw, reset the gap
and tightening the screw in the new position. Reattach
the lead removed earlier, and reinstall the case side.
MAINTENANCE
D-3
D-3
SQUARE WAVE TIG 275
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.015 Spark Gap
RIGHT SIDE VIEW OF MACHINE
FIGURE D.1 SPARK GAP