Lincoln Electric 10120 Operator's Manual page 32

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PC BOARD TROUBLESHOOTING GUIDE -
1. All 10 LEDʼs must be ON when the POWER SOURCE is turned ON and the wire feederʼs trigger is closed, or
a jumper is placed between 2 & 4, or the "OUTPUT TERMINALS SWITCH" is in the ON position.
2. LEDʼs 7, 8, and 9 indicate AC power being supplied to the P.C. board from auxiliary windings (T1). If a light is
not on, turn the machine off and unplug P5 from the firing board. Turn the machine back on and check the fol-
lowing voltages:
Light that was off
7
8
9
3. If all voltages are present, turn power off, and plug P5 back into J5. Turn power back on. If LEDʼs are still out,
replace firing Printed Circuit Board (PCB).
4. If voltages were not present then check the wiring back to the auxiliary windings for a possible open.
5. LED 10 senses when 2 and 4 are closed. Close 2 & 4, LED 10 should be "on". Open 2 & 4, LED 10 should be
"off".
6. LEDʼs 1 through 6 indicate gate signals are being sent to the main SCRʼs 1 through 6 respectively If LED5 is
on (CONTROL BOARD), along with LED7, 8, and 9 on firing (PCB), and LEDʼs 1 through 6 are not on, check
to make sure lead 231 between control board and firing board is not broken.
7. If any one of LED 1 through 6 are not on and LEDʼs 7,8, and 9 are on, replace the firing (PCB) .
PC BOARD TROUBLESHOOTING GUIDE -
1. LED1 indicates AC input voltage necessary to generate the DC supply voltages is present. These voltages
power the control board circuitry. LED2 indicates the -10V supply is OK. LED3 indicates the +16V supply is
OK. If LED1, 2, or 3 are not ON when machine POWER IS ON, Replace Printed Circuit Board.
2. LED4 should not be on. If this LED comes on while welding, the machine will phase back to about 10 amps
and stay there. This was do to either a short across output, or a current draw of about 1000A. Remove short
or reduce output current. If no short or 1000 amp load exists, replace Control Printed Circuit Board.
3. LED5 indicates control voltage is present. With trigger circuit OPEN and CONTROL POT set to minimum,
LED5 should be very bright. Closing trigger circuit and Turning CONTROL POT towards maximum, LED5
should dim and then go out. Replace Printed Circuit Board if LED5 does not go ON.
4. LED6 indicates trigger condition. LED6 ON indicates trigger is CLOSED. LED6 OFF indicates trigger is OPEN.
If LED6 does not come ON, look for open connections in the 2 & 4 circuit.
5. LED7 indicates welder output voltage is being sensed on the control board. When turning the Control Pot
towards maximum, LED7 should glow brighter. If LED7 does not light, made sure lead 222 from the negative
output lead is connected to J1 PIN 14.
6. LED8 indicates a fault condition. When LED8 is ON the machine is phased back to 10 amps and will stay
there until the POWER SWITCH is turned OFF then back ON. This fault is do to a short across welderʼs out-
put, or 1000 amp current draw. If no short or 1000 amp load exists, replace Control Printed Circuit Board.
7. LEDʼs 9 & 11 should be OFF on CV-655 machines.
8. LED10 should be ON when machine power is ON. If not replace Control (PCB).
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact your
Local Lincoln Authorized Field Service Facility for technical troubleshooting assistance before you proceed.
TROUBLESHOOTING
Observe all Safety Guidelines detailed througout this manual
Check AC voltage between
P5 pins 15 & 16 (wires 203,204)
P5 pins 7 & 8 (wires 205,206)
P5 pins 5 & 6 (wires 207,208)
FIRING PRINTED CIRCUIT BOARD
CONTROL PRINTED CIRCUIT BOARD
CAUTION
CV-655
Voltage should be approximately
32VAC
32VAC
32VAC
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