Lincoln Electric SQUARE WAVE TIG 355 Service Manual page 42

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MAINTENANCE
SAFETY PRECAUTIONS
WARNING
• Only Qualified personnel should
perform this maintenance.
• Turn the input power OFF at the
disconnect switch or fuse box
before working on this equipment.
• Do not touch electrically hot parts.
INPUT POWER FACTOR
CAPACITOR DISCHARGE
PROCEDURE
This procedure ensures that the power factor capaci-
tors are discharged, for greater safety when you are
working on the Square Wave TIG 355 with INPUT
POWER REMOVED.
1. Remove input power to the machine.
2. With a 5/16" nutdriver, remove the sheet metal
screws that hold the right case side in place.
Remove the right case side.
3. With a volt/ohmmeter, carefully check the voltage
across the input power factor capacitors. When
input power is removed, the voltage across each
capacitor should be zero. (Normally, the capacitors
discharge through the primary winding in the main
transformer.)
4. If capacitor voltage is zero, you may begin working
on the Square Wave TIG 355.
SQUARE WAVE TIG 355
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