Lincoln Electric POWER WAVE C300 Service Manual page 36

F-17
CASE COVER REMOVAL AND DC LINK CAPACITOR
CHOPPER
CONTROL
BOARD
PLANAR
TRANSFORMER
DC LINK CAPACITOR
CURRENT TRANSDUCER
CAPACITOR DISCHARGE PROCEDURE
1. Disconnect the input power to the POWER
WAVE® C300 machine.
2. Be careful not to make contact with capacitor ter-
minals located on the left side of chassis as
shown in Figure F.2.
3. Carefully check for DC voltage at the capacitor
terminals. See Figure F.3.
4. If the capacitor voltage is present discharge the
capacitor as follows.
5. Using a high wattage resistor (25-1000 ohms @
25 watts (minimum), electrically insulated gloves
and pliers hold the resistor terminals across the
capacitor terminals for 10 seconds
WARNING
ELECTRIC SHOCK can kill.
High voltage is present when input
power is applied to the machine.
TROUBLESHOOTING AND REPAIR
DISCHARGE PROCEDURE (continued)
FIGURE F.2 – CAPACITOR LOCATION
INPUT CHOKE
POWER WAVE® C300
DO NOT TOUCH THE CAPACITOR TERMINALS
WITH YOUR BARE HANDS.
NEVER USE A SHORTING STRAP FOR THIS PRO-
CEDURE.
ALSO CAREFULLY CHECK FOR A DC VOLTAGE
AT B48 - B49. SEE FIGURE F.9. IF A VOLTAGE IS
PRESENT WAIT FOR IT TO DECAY BEFORE PRO-
CEEDING.
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6. Recheck the voltage across the capacitor termi-
nals. The voltage should be zero. If any voltage
remains, repeat the procedure. NOTE: Any volt-
age present after discharge has been performed
is an abnormal condition and may indicate a
switch board problem.
F-17