Troubleshooting for VBUS faults (3-00-0)

A 3-00-0 fault indicates that the Direct Current (DC) bus voltage (VBUS) is out of range.

Fault codes and fault LEDs


Fault code	Fault LEDs	Torch LED	Description	Stops the system from operating?
3-00-0	ON	Red	The DC bus voltage (VBUS) is out of range.	Yes

Corrective action for VBUS faults using test points (3-00-0)

Do a test of the power Printed Circuit Board (PCB) to make sure that the circuits are balanced. Use the test points on the power PCB to do the test. There are labels on the rear of the power PCB for the test points (TP1, TP2, TP3).

Use miniature banana plugs to connect to the test points on the power PCB as shown in this procedure. Refer to Required test equipment.

The image shows a miniature banana plug.

If miniature banana plugs are not available, use small test clips that you can attach to the copper contacts in the test point openings on the power PCB.

Notice

DO NOT CONNECT -VBUS TO GROUND

Do not connect -VBUS (TP1) to ground. This can cause damage to the plasma power supply so that it becomes unserviceable.

Notice

SHORT CIRCUIT BETWEEN BUS AND HEATSINK IS POSSIBLE

Do not use a multimeter with test leads for this test. This can cause a short-circuit between the BUS and the heatsink. Use mini-banana plugs for this test, and attach them to the test point (TP) openings in the power PCB.

Set the power switch to OFF (O), disconnect the power cord from the power source, and disconnect the gas supply.
Remove the plasma power supply handle and cover.
Remove the component barrier.
Reconnect the electrical power, but keep the power switch set to OFF (O).
Measure the voltage between the TP1 and TP2 test points.
1. Put the mini-banana plugs at TP1 and TP2 on the power PCB.
2. Set the power switch to ON (I).
3. Make sure that the voltage is approximately:
  - 280 VDC/340 VDC for 200 V/240 V 1-phase models
  - 560 VDC for 400 V CE/CCC 3-phase models
  - 670 VDC for 480 V CSA 3-phase models
Measure the voltage between the TP1 and TP3 test points.
1. Set the power switch to OFF (O).
2. Move the mini-banana plugs to TP1 and TP3 on the power PCB.
3. Set the power switch to ON (I).
4. Make sure that the value is approximately one-half of the value from step 5:
  - 140 VDC/170 VDC for 200 V/240 V 1-phase models
  - 280 VDC for 400 V CE/CCC 3-phase models
  - 335 VDC for 480 V CSA 3-phase models
  All values can be ±10%.
Measure the voltage between the TP2 and TP3 test points.
1. Set the power switch to OFF (O).
2. Move the mini-banana plugs to TP2 and TP3 on the power PCB.
3. Set the power switch to ON (I).
4. Make sure that the value is approximately one-half of the value from step 5:
  - 140 VDC/170 VDC for 200 V/240 V 1-phase models
  - 280 VDC for 400 V CE/CCC 3-phase models
  - 335 VDC for 480 V CSA 3-phase models

Are the voltages in step 6 and step 7 approximately equal, and is the capacitor resistance in the correct range? OptionDescription

If yes...	If you cannot find or correct the problem, a qualified service technician must repair the system. Speak to your distributor or authorized repair facility.
If no...	If the voltage values are different by more than 30 V, and if the capacitor resistance is out of range, replace the power PCB. Refer to Remove the power PCB.

Corrective action for VBUS faults using the capacitor terminals (3-00-0)

Do a test of the power PCB to make sure that the circuits are balanced. Use the capacitor screws to do the test. There are labels on the rear of the power PCB for the positive (+) and negative (-) capacitor terminals.

Warning

ELECTRIC SHOCK CAN KILL

Let the system release internal voltages before you touch the capacitors. The capacitors can hold a charge for several minutes after the system is set to OFF.

Wait approximately 10 minutes for internal voltages to discharge.
Loosen the capacitor screws enough that you can disconnect the capacitors from the power PCB.
Measure the resistance across the capacitors, and make sure that the resistance is approximately:
- 13.5 kiloohms (kΩ) for 1-phase models
- 18 kiloohms (kΩ) for 3-phase models
Do a visual inspection of the capacitors.

Replace the capacitors if you do not see white dots in the vent holes next to the capacitors, as shown.

Always replace both capacitors at the same time.

Refer to Remove the bulk capacitors.

The image shows the capacitor screws and the white dots in the vent holes in the power Printed Circuit Board.

1	Capacitor screws
2	Vent holes