Thermal Dynamics PakMaster XLPLUS 50 - 4.06 Main Input and Internal Power Problems; A. Main power line fuses blow as soon as main disconnect is closed; B. Main power line fuses blow 3-6 seconds after the ON;OFF Switch is turned on; C. AC indicator on front panel of power supply is OFF; Fan does not operate

SECTION 4: SERVICE TROUBLESHOOTING 16 Manual 0-2745
D. Main Arc Test
Press the Torch Switch to establish a pilot arc.
Bring the torch to within 1/8"-3/8" (3.2 - 9.5 mm) of the
workpiece to establish the main cutting arc, and note the
following:
• Main cutting arc initiates
• Pilot Relay opens
This completes the Main Arc Test. If the above are all
correct then the equipment should be operating properly.
If problems still persist then contact Technical Services.
If the above does not function as noted then note the
symptom and proceed to Section 4.08, Main Arc Prob-
lems.
4.06 Main Input and Internal Power
Problems
Locate your symptom below:
A. Main power line fuses blow as soon as main
disconnect is closed
1. Input power cable installed incorrectly
a. Refer to Operating Manual 0-2744, Section 3.07
and connect primary input power cable.
2. Input voltage selection incorrect for the main input volt-
age
a. Refer to Operating Manual 0-2744, Section 3.06
and select proper input voltage
B. Main power line fuses blow 3-6 seconds after the
ON/OFF Switch is turned on.
1. Faulty Input PC Board and Rectifier
a. Test Input PC Board/Rectifier per Section 4.09-
D; repair as necessary
2. Faulty FET PC Board
a. Test FET PC Board per Section 4.09-I; repair as
necessary
C. AC indicator on front panel of power supply is
OFF; Fan does not operate
1. Front Panel ON/OFF switch in OFF position
a. Place switch to ON position
2. Main power disconnect not closed
a. Close main power disconnect
3. Main power line fuses blown
a. Replace main power line Fuses
4. Defective input power cable
a. Replace input power cable
5. Improper input power line connections inside Power
Supply
a. Refer to Operating Manual 0-2744, Section 3.07
and correct if needed
6. Fuse blown inside Power Supply
a. Replace internal Fuse (1 FU)
7. Line voltage above 10% tolerance (over voltage protec-
tion)
a. Reduce line supply.
8. Voltage selection plug connected incorrectly
a. Refer to Operating Manual 0-2744, Section 3.06
and correct as needed
9. Faulty Auxiliary Transformer (refer to Appendix X, 36
VAC Circuit Diagram)
Measure for 36 VAC on Logic/Gate PC Board from
J1-1 to J1-5.
a. If voltage is not present, replace the Auxiliary
Transformer.
10. Faulty Logic/Gate PC Board (refer to Appendix X, 36
VAC Circuit Diagram).
Measure for 36 VAC on Logic/Gate PC Board from
J3-1 to J3-3.
a. If voltage is not present, replace the Logic/Gate
PC Board.
11. Faulty ON/OFF switch (refer to Appendix X, 36 VAC
Circuit Diagram).
Measure for 36vac on the Logic/Gate PC Board
between J3-2 to J3-4.
a. If voltage is not present replace the ON/OFF
switch
b. If voltage is present, replace Logic/Gate PCB.
D. AC indicator ON, TEMP indicator ON, System
will not pilot
1. Air flow through unit is restricted
a. Provide adequate air flow (Refer to Operating
Manual 0-2744, Section 3.02)
2. Exceeded duty cycle of Power Supply