Lincoln Electric DC-655 Operator's Manual page 33

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PC BOARD TROUBLESHOOTING GUIDE -
BOARD
NOTE:
Fan will run for minimum of 5 minutes once fan turns on.
1. LED1 when ON indicates fan should be running. If ON and machine is cold, replace PCB.
2. LED2 when ON indicates welding current greater than 50 amps. If ON and not drawing more than 40 amps,
replace PCB.
3. LED3 when ON indicates Main SCR'S need cooling and turns fan ON. If ON and machine is cold, replace
PCB.
4. LED4 when ON indicates an open Thermal Fan Thermistor, or open connection to PCB. Fan will run constant-
ly. Check Thermal Fan Thermistor for an open. If open replace. If not open Replace PCB.
5. LED5 when ON indicates an open thermostat. Thermal Protection light should also be ON. If Thermal
Protection light is not ON, and LED5 is ON, replace PCB.
6. LED6 when ON indicates fan should be running. LED6 will be ON whenever LED's 2, 3 4 or 5 is ON. If LED's
2, 3, 4, or 5 are not ON when LED6 is ON, replace 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
THERMAL FAN/ SNUBBER P.C.
CAUTION
DC-655
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