Tweco 51 with SL100SV CutMaster - Manual (Page 96)

SERVICE 5-32 Manual 0-4640
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 #7 and #8. 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
When the unit is at “idle” the AC indicator on the Front Panel should be ON. When the torch is activated, the gas begins to
flow. When the preflow time is over, the INV ON indicator on the Logic PCB energizes, and the DC indicator on the Front
Panel turns ON.
• If the INV ON indicator does not turn ON, then replace the Logic PCB.
• If the INV ON indicator turns ON then OFF immediately, the following test should be performed:
a. Disconnect eight-pin wire harness connector from the Pilot PC Board.
WARNING
The connector on the Pilot PC Board must be disconnected to prevent electrical damage to measuring equipment
when testing the open circuit voltage (OCV).
b. Activate torch (Logic PC Board Inverter On Indicator, turns ON).
c. Measure for more than 200 vdc between E7(+) and E10 (-) on the Main PC Board. If voltage is less than 10 vdc, each
IGBT Module and Output Diode Module should be tested individually.