Tweco CutMaster 101 with SL100SV - Manual (Page 89)

Manual 0-4642 5-25 SERVICE
5
6. Faulty Main PC Board or Logic Board.
a. Measure for ±0 vdc at TP2 to TP1 on the Logic Board when attempting to transfer. Refer to Logic Board Layout.
• If TP2 goes to 0 vdc replace Output Board.
• If not, replace Main PC Board.
7. Faulty Main Input Contactor.
a. Check per Subsection 5.14-D.
B. When operating the amperage drops off after the main cutting arc starts.
1. Torch tip contacts workpiece
Raise the torch tip off the work. At output settings over 40 amps, circuitry in the power supply automatically reduces
output current to 40 amps if the torch tip contacts the workpiece.
2. Faulty Pilot Board
a. With power off and wires E58 and E62 disconnected from the pilot board, measure for continuity between terminals
#E58 and #E62. If continuity is found, replace Pilot Board.
5.08 Test Procedures
The test procedures in this subsection are referenced in the troubleshooting section.
A. Safety Precautions
1. Significant DC Voltage exists after removal of input power. Allow two minutes for discharge time. Voltage measured on input
capacitors must be zero before performing service on the power supply.
2. Do Not touch electrical components with any part of the human body when power is applied.
3. Keep away from any moving parts.
4. Hot surfaces can cause severe burns. Allow equipment to cool before servicing.
5. Electrostatic discharge can damage printed circuit board assemblies. Transport printed circuit boards in proper antistatic
shielded packages. Use proper grounding techniques with wrist strap before handling printed circuit boards.
6. Misaligned plugs can cause printed circuit board damage. Be sure plugs are properly aligned and completely seated.
7. Excessive pressure can damage printed circuit boards. Use only minimal pressure and gentle movement when disconnecting
or connecting printed circuit board plugs.