Open Circuit Voltage Check - Thermal Dynamics C-70A CUTSKILL Service Manual

6.04 Open Circuit Voltage Check

1. Attach shop air to unit.
2. Remove torch consumables from torch head and replace the shield cup.
3. Turn unit power on. (220VAC 1PH). LD2 on both the Control Board and the PWM Board should be on and the
cooling fan running.
4. Refer to the 230V schematic in Appendix. Measure terminal TB1, Pin 1 (Red) and pin 3 (Black), it should be 220
VAC (incoming voltage).
5. Refer to following photo. Measure Output voltage of the Input Diode Terminals 1(Black) and 2 (White). It should
be 320 VAC.
6. Depress the torch trigger. Air should flow.
7. Check for illumination of the LD2 on both the Control Board and the PWM Board. They should both brighten.
8. Measure IGBT output to Main Transformer between points 12 and 13. It should be 220 VAC
9. Measure output OCV between points 7 and 9. It should be 290 VAC.
10. Turn off the unit power and replace the torch consumables removed in step 2 above.
Art # A-07055
Input Diode
O.C.V. Measured
between
these points
9
Manual 0-4699
Diode Outputs
1
5
4
3
Output Diode
6
7
8
2
P5
Thermal SW
P5
6-5
IGBT Outputs
(-)
(+)
10
11
12
IGBT Output
13
TROUBLE SHOOTING