Thermadyne CE CutMaster 75, Service Manual

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SERVICE TROUBLESHOOTING 4-6 Manual 0-2869
2. Main power disconnect not closed
a. Close main power disconnect.
3. Main power line fuses blown
a. Replace main power line fuses.
4. Improper input power cable connections inside Power
Supply
a. Refer to System Schematic and correct if
needed.
5. Defective input power cable
a. Replace input power cable. Refer to Section
5.07-E.
6. Fuse blown inside Power Supply
a. Replace internal Fuse per Subsection 5.06-A.
7. Line voltage above 10% tolerance (over voltage pro-
tection)
a. Reduce line supply.
8. Faulty Auxiliary Transformer (refer to Appendix 12,
28 VAC Circuit Diagram)
Measure for 28 VAC on Main PC Board from
J18-4 to J18-3.
a. If voltage is not present, replace the Main PC
Board.
J23-1
J23-3
A-03171
Main PC Board
J18-5
J18-6
J24-3
J24-4
J18-3
J18-4
9. Faulty ON/OFF switch (refer to Appendix 12, 28 VAC
Circuit Diagram).
Measure for 28 VAC on the Main PC Board be-
tween J18-5 to J18-6.
a. If voltage is not present replace the ON/OFF
Switch.
J23-1
J23-3
A-03171
Main PC Board
J18-5
J18-6
J24-3
J24-4
J18-3
J18-4
10. Faulty Main PC Board (refer to Appendix 4, Main PC
Board Layout).
Measure for 12 vdc on Main PC Board from TP4
to TP6.
a. If voltage is not present, replace the Main PC
Board.
D. System will not pilot; AC indicator ON, TEMP
indicator ON
1. Air flow through unit is restricted
a. Provide adequate air flow (Refer to Operating
Manual, Subsection 3.02, Site Selection).
2. Exceeded Duty Cycle of Power Supply
a. De-activate torch and wait for fan to cool unit.
Refer to Section 3 for proper duty Cycle for this
unit.
3. Faulty Fan(s)
Measure for 230 VAC (±) on the Main PC Board
from J15-1 to J15-5, and from J15-2 to J15-6.
• If voltage at J15-1 to J15-5 is correct, replace
lower Fan (M1).
• If voltage at J15-2 to J15-6 is correct, replace
upper Fan (M2).