Thermal Dynamics Pak Master 75XL Plus, Service Manual

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TROUBLESHOOTING 4-8 Manual 0-2747
5. Faulty torch
a. Check continuity per appropriate Torch Instruc-
tion Manual.
6. Faulty connection of wire #16 or #17 to Pilot Output
PC Board
a. Check wiring connection.
A-01400
Pilot Output PC Board
E23
Wire #17
E24
Wire #16
To
p
7. Faulty Logic/Gate PC Board
Check D39 & D20 on the Logic/Gate Board.
a. If D39 and D20 are not on, replace Logic/Gate
PCB.
Measure for 12 vdc on Logic/Gate PC Board from
J5-6 to J5-7.
a. If voltage is greater than 2vdc, replace Logic/
Gate PC Board.
Measure for 15 vdc on Logic PC Board from J5-6
to J5-7.
4.08 Main Arc Problems
Locate your symptom below:
A. Main cutting arc will not start.
1. Work cable not connected.
a. Connect work cable.
2. Faulty current sensor
Check the following indicators inside the Power
Supply:
• Pilot indicator (D39) on the Logic/Gate PC
Board is ON during pilot then OFF during main
arc transfer.
• CSR indicator (D20) on the Logic/Gate PC
Board is OFF during pilot then ON during main
arc transfer.
While trying to transfer, measure voltage at J17-1
to J17-2 on the Logic/Gate PC Board.
If voltage is approximately 12vdc replace the
Current Sensor.
If voltage is less than 2vdc replace the Logic/
Gate PC Board.
Logic/Gate PC Board
D20 D39
J17
Pin 1
Pin 2
D36
A-02549
B. When operating at amperages over 35 amps the
amperage drops off after main cutting arc initiates
Check the following indicator inside the Power Sup-
ply:
• Drag indicator (D36) on the Logic/Gate PC
Board is ON when the torch tip comes in con-
tact with the workpiece.
1. Cutting tip in contact with the workpiece.
a. Maintain standoff distance 1/8"-3/8" (3-9 mm)
between cutting tip and workpiece. (See SW-1
Drag Disable).