ESAB ESP-50 Manuel D'instruction page 230

sectIon 6
3. Does air flow when "air test" switch is in test position?
a. If not, check torch consumables, replace if necessary.
b. If above items check OK , the problem is internal. Take unit to an
Authorized Repair Station for repair.
d. the power light is on, but nothing happens when the torch switch is de-
pressed. Fault light does not activate.
1. check the following:
a. With the machine power on, depress the torch switch. on the control
board the led 1 should be lit as long as the switch is depressed. If not
then check:
i. turn power off to the machine. unplug control board. put an ohm-
meter across p5-1 and p5-2 to take resistance reading. depress
torch switch. meter should read a short. If not, then one of the
following is not working properly:
ii. torch switch or the leads. unplug the torch switch leads at the
machine. put a meter across the two plug pins. should read a short
when the torch switch is depressed. If not, then either broken
switch leads or malfunctioning switch.
b. check t2 transformer secondary voltages at the plugs p1 and p2. refer
to system schematic. replace the transformer if the correct secondary
voltages are not present.
c. If everything above checks out all right, then the pcb1 control board
should be replaced.
e. Fault light activates when torch switch is closed.
the Fault circuit is used to monitor conditions necessary for the safe op-
eration of the esp-50. the fault light will glow amber under the following
conditions and operations will come to a complete stop:
1. high/low line voltage. The Fault Light will rapidly blink on and off
(5 times per second). This indicates that the input voltage is outside the "+" or
"-" 15% safe operating range rating.
2. over temperature. The fault light will be mostly off but will blink on for
1/10th of a second, every second. this generally indicates that the duty
cycle has been exceeded. allow the power source to cool before returning
to operate.
a. thermal switch may be open. It will open if the temperature at the IGbt
base reaches 94°c. With the machine power off, check the continuity
between p1-1 and p1-2 of the control board. If the switch is oK, then
the ohmmeter should read a direct short. If not then it should read
open.
b. If the switch is malfunctioning, replace it. clean the surface of the heat
sink before installing the switch.
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troubleshootInG