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TROUBLESHOOTING & REPAIR
ARC START TRIGGER CIRCUIT TEST (continued)
FIGURE F.2 – 6-PIN AMPHENOL RECEPTACLE
F
A E
BD
C
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TEST PROCEDURE
1.Remove input power to the machine.
2.With the 5/16" nut driver, remove the screws and carefully lower the front control panel.
3.Locate plug J9 on the control PC board.
WARNING
ELECTRIC SHOCK can kill.
•With input power ON, there are high voltages inside the machine. Do not reach into the machine or touch any internal part of the machine while power is on.
4.Turn on input power to the machine.
5.Close the Arc Start switch or jumper pins "D" to "E" at the
6.With the volt/ohmmeter, check for 24 VAC at pins 1J9 to 3J9.
•If 24 VAC is present, the control PC board may be faulty. NOTE: 24 VAC should be present at pins 1J9 to 3J9 only when the Arc Start switch is closed.
•If 24 VAC is missing or low, check for 24 VAC at the T5 transformer. See the Wiring Diagram. If 24 VAC is missing or low at the transformer leads, perform the Control Transformer Test.
•If 24 VAC is present at the transformer leads, remove input power to the machine and check the continuity and resistance of the leads and coils on and between the feed- thru board and the protection board. See Figure F.3.
7.Also check the continuity of the leads from the protection board to the
8.After the tests are complete, install the front control panel, using the 5/16" nut driver.
SQUARE WAVE TIG 355