Lincoln Electric IM422 PRO-CUT 40 - Manual (Page 16)

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SYMPTOM CHECK
b. If there is 115VAC between J18-1 and
J18-4, check for less than 0.5 VDC
between J5-5 (+, lead number 255A or
255B) and J5-2 (-, lead number 272).
If voltage is OK, replace the air
solenoid. If voltage is high, (approx.
5.5 VDC), replace the pressure switch.
B. If the air functions properly in “PURGE”,
switch the machine back to the “RUN” mode.
The air should continue to flow and the “AIR
PRESSURE” LED should remain on for 5 to
20 seconds. If air now functions properly,
replace the MICRO CONTROL BOARD. If
the air does not function properly, perform
step 4.A.2.
The air begins to flow, the “OUTPUT ON” LED lights 1. Check the torch consumables to be sure they
for a brief period and then the “MALFUNCTION” LED are in tight, not dirty or greasy, and in good
turns on until the trigger is released. No arc is shape. Replace the consumables if necessary.
established. 2. Check for 380VAC between leads H4 and H1
at the auxiliary transformer, T1. Replace the
transformer, T1, if not correct.
3. Check for 115VAC between J5-9 (lead number
215) and J5-6 (lead number 215A) at the auxil
iary transformer, T1. If voltage is not correct,
replace the transformer, T1.
4. Check for 115VAC between J19-9 (lead number
215B) and J19-7 (lead number 215D) at the
high frequency module. 115VAC should be
applied for approximately 1/2 second while the
“OUTPUT ON” LED is turned on.
A. If there is not 115VAC between J19-9 and
J19-7, check for < 0.5 VDC between J16-4
(+, lead number 504) and J16-1 (-, lead
number 501). Replace the PWM CONTROL
BOARD if the voltage is OK, or replace the
MICRO CONTROL BOARD if the voltage
remains high, approximately 15 VDC.
B. If there is 115VAC between J19-9 and J19-7
check for less than 0.5 VDC between J5-5
(+, lead number 255A or 255B) and J5-2
(-, lead number 272). If voltage is OK,
replace the air solenoid. If voltage is high,
approximately 5.5 VDC, replace the
pressure switch.
5. Check for a high frequency enable signal be-
tween J3-1 (+, lead number 327) and J1-1 (-,
lead number 501). The signal should be a 15V
square wave at a 60 Hz frequency for approx.
1/2 second while the “OUTPUT ON” LED is
turned on. If the signal remains high (+15 VDC)
replace the MICRO CONTROL BOARD. If the
enable signal is present, replace the HIGH
FREQUENCY MODULE.
6. Check pilot to work for a value between 6 and
10 ohms of resistance.
7. Check each 300W resistor for its rated value.
Replace if bad.
8. Replace PWM CONTROL BOARD.
9. Replace MICRO CONTROL BOARD.