.A complete Parts List is available at www.MillerWelds.com
6-4. DC Bus Voltage Check
Y440 Volts DC can be present on the capacitor bus and significant DC voltage can remain on capacitors after unit is Off. Always check the voltage on inverter assembly as shown to be sure the input capacitors have discharged before working on unit.
2
1
5
YTurn Off welding power source, and disconnect input power.
YSignificant DC voltage can remain on capacitors after unit is Off. Always check the voltage as shown to be sure the input capacitors have discharged before working on unit.
Remove wrapper from unit (see Section
1Circuit Board PC1
2Voltmeter
3TP5 Pin 5
4TP5 Pin 1
YCheck DC bus voltage before servicing. Set multimeter to read voltage. Check voltage between TP5 pins 1 and 5. Volt- age should read 5 volts DC or less.
.If the capacitor voltage does not drop to near zero after several minutes, use a bleeder resistor of between 200 and 500 ohms, at least 10 watts, and #16 AWG 600 volts ac in- sulation rated wire to discharge the capacitor(s).
5 Typical Bleeder Resistor
An example of a typical bleeder resistor is shown on this page.
Proceed with job inside unit. Reinstall wrapper when finished.
Typical Bleeder Resistor
200 to 500 ohm, 10 watt
wire wound resistor
#16 AWG 600 Volts AC
Insulation Rating
Tools Needed:
Torx 25
Ref. 804
