Hypertherm Powermax125 Service Manua - Manual (Page 163)

Powermax125 Service Manual 808070 163
8 – Troubleshooting and System Tests
Test 10 – Pressure sensor
Symptom: The pressure sensor reading does not agree with known pressures.
 Wear proper personal protective equipment (PPE) before testing powered equipment.
1. Remove the white cover on the plug at J3 on the power board.
2. Turn the machine ON.
3. Measure power to the sensor between pin 2 (-) and pin 3 (+).
If not 5.0 VDC (±5%), perform Test 5 – Flyback circuit (DC minor voltages) on page 156.
4. From the service screen, enable the gas test.
Note the flowing gas pressure in the “P” field to the right of the slash.
5. Measure VDC between pin 2 (-) and pin 1 (+).
The value should be 0.0463 times the pressure, for example (68 psi * 0.0463 VDC/psi = 3.148 VDC).
If the voltage measurement is within ±10% of the correct value and you have a pressure alert or fault:
a. Test with a known working DSP board.
b. If the measured voltage is correct, replace the DSP board.
c. If the measured voltage is not correct, replace the pressure sensor.