Tweco CutMaster 101 with SL100SV - Manual (Page 94)

SERVICE 5-30 Manual 0-4642
5
E. Gas Solenoid Circuit Test
Make the following voltage checks and replace the faulty part as required.
1. Place the RUN / RAPID AUTO RESTART / SET Switch to the SET position.
2. Measure for 28 VAC across Solenoid wires #8 and #9. Refer to System Schematic in Appendix Section.
• If 28 VAC is present, replace Solenoid/Pressure Switch Assembly.
• If 28 VAC is not present, check for 65 psi (4.5 bar) at the pressure regulator.
3. Check for less than 2 vdc at P1-7 to TP1 on Logic Board.
• If less than 2 vdc, replace Main PC Board.
• If more than 2 vdc, replace Logic PC Board.
F. Output Power Tests
1. No DC Output
a. Activate the torch.
• If INV ON indicator D13 on Logic PC Board does not turn ON, then replace the Logic PCB.
• If the INV ON indicator D13 blinks ON then OFF immediately, perform the following test:
WARNING
The following tests must be performed with the power supply connected to primary input power. There are
extremely dangerous voltage and power levels present inside this unit. Do not attempt to diagnose or repair
without proper training in power electronics measurement and troubleshooting techniques.
The next step will defeat the safety interlock feature. Proceed with caution.
b. Remove the tip and electrode from the torch. Attach the work lead to the pilot return (E35 or E62) on the Output Power
Board. Activate the torch switch. Gas should flow, then stop after 2 seconds. Front panel DC indicator should
turn on.
c. Measure open circuit voltage between E61(+) to E43 (-) at the Output Power PC Board. Voltage should be greater than
200 V. If voltage is less than 10 V, refer to the diode test measurements in Section 5.10-C.
2. Gate Drive & Sensing
a. After checking all previous steps, jumper TP1 to TP7 on the Logic PCB. Refer to Logic Board layout.
b. When the unit is turned on, the DC light should remain ON.
c. Activate the torch. After two seconds INV ON Indicator (D13) on the Logic PCB should come on and remain on.
• If INV ON indicator does not remain on, replace Logic PCB.
• If INV ON indicator remains on, then check for at least 2 vdc between TP-1 to TP-11 and between TP-1 to TP-10 on the
Logic PCB. Refer to Logic Board Layout.
• If no voltage, replace Logic PC Board.
• If voltage is correct, measure for at least 2 vdc between points as in the following chart:
E11 J2A E11 J2B
E19 J10A E19 J10B
IGBT A IGBT B
• If voltage is 0, replace Main PCB.