Lincoln Electric PRO-CUT 55 SVM140-A Service Manual page 78

F-41
FIGURE F.10 - OUTPUT BOARD TRIGGER CIRCUIT TEST POINTS AND LEDS
G3326 PRO-CUT 55 OUTPUT
LED1
+
C13
PRO-CUT 55 OUTPUT BOARD
LED DEFINITIONS
LED1: (Red) This light indicates that 24 VAC is
being supplied to the output board from the aux-
iliary transformer. It also shows that the 24 VAC
is being rectified to approximately 28 VDC. This
DC voltage is used for the "parts-in-place"
check for the torch circuit.
LED2: (Red) This light indicates that 12 VAC is
being supplied to the output board from the aux-
iliary transformer. It also shows that the 12 VAC
is being rectified to approximately 17 VDC. This
DC voltage is used to power the trigger circuit
and solenoid driver circuits incorporated on the
output board.
LED3: (Green) This light indicates that the air
solenoid driver circuit is functioning. When this
LED is lit, the air solenoid should be activated.
TROUBLESHOOTING & REPAIR
TRIGGER CIRCUIT TEST (continued)
LED3
J31
LED5
LEAD#2
LEAD#4
J32
LEAD#312
LEAD#344
D25
J30
LED4
LED2
PRO-CUT 55
G3326-2,3
LED6
LED5
LED3
LED1
LED2
LED4: (Green) This light indicates that the trig-
ger circuit on the output board has been activat-
ed. This LED should be lit when the torch or
remote trigger is closed. This trigger circuit, on
the output board, then sends a signal to the
control board.
LED5: (Green) This light indicates that the elec-
trode solenoid driver circuit is functioning. When
this light is lit, the electrode solenoid should be
activated. The electrode solenoid should be
energized during gas (air) pre-flow time. During
pilot and cutting arc periods, the LED should be
off. When the arc goes out, the machine enters
the post-flow state. Two seconds after the start
of post-flow the electrode solenoid is activated a
few times. The LED should blink to indicate this
activity. The electrode solenoid will then be
energized for the duration of post-flow. (The LED
should be on.)
LED6: (Green) Indicates gate drive for pilot
transistor.
F-41
LED4