Diagnostics and Troubleshooting
XPR300 Instruction Manual 809480 323
5. If the fan speed is within acceptable range, remove the power from the cutting system. Refer to
Remove the power from the cutting system on page 240.
6. Remove the pump-side and front panels of the plasma power supply.
7. If you find obstructions, debris, or dust, use compressed air to remove the obstruction, debris, or
dust from the fans and heat-exchanger area.
The heat-exchanger area can retain large amounts of dust or debris.
Multiple uses of compressed air is often necessary to clear this area.
Consider the use of personal protective equipment to protect yourself
from airborne particulates and debris.
Make sure to minimize fan rotation during compressed air use. You can
use a gloved hand to hold a fan in position, if necessary.
8. Make sure that the heat-exchanger fans have no obvious obstruction, dust, or debris:
a. Disconnect the connector for the choppers or remove the coolant thermistor wires from the
connector. This makes it easier to measure only the resistance for the thermistors.
b. Use a digital multimeter to measure the resistance from each thermistor wire, based on the
following codes and connector-pin locations:
c. Look for a resistance value that is outside of the minimum or maximum in Table 37:
Diagnostic code Thermistor location
Location of thermistor
wires / connector
Pins
587, 670, 681 Heat exchanger, top PCB 1 J1.2 pin 7 J1.2 pin 8
560, 667, 678 Chopper 1 (cold plate) PCB 2 J9 pin 1 J9 pin 2
561, 668, 679 Chopper 2 (cold plate) PCB 3 J9 pin 1 J9 pin 2
85 750 1250
95 600 1000
105 400 800
115 300 600
125 200 500
135 150 400
145 150 250
155 125 225
165 100 175