MK Products CobraMig 260 PS/Feeder - Manual (Page 33)

CobraMig 260 Owner's Manual - Page 27
FLOW CHART
NO
CAPACITORS SHORTED
YES
PROBLEM AREA
POWER TRANSFORMER "T1", DIODES, CAPACITORS
SYMPTOM
DISCONNECT FUSE BLOWS WHEN TORCH IS TRIGGERED
START
USING AN OHM METER, MEASURE THE RESISTANCE AT J6-1
(WELD VOLTS) AND J6-2 (WORK GROUND) ON COBRA I MAIN
BOARD, READING SHOULD BE APPROX. 25 OHM
TURN OFF ALL POWER
AND DISCONNECTS
NO YES
IS READING OK ?
POWER TRANSFORMER "T1"
IS DEFECTIVE
DISCONNECT DIODES FROM
POWER TRANSFORMER T1 :
ANODE D1 FROM T1-6
ANODE D2 FROM T1-5
IS READING AT J6-1 AND J6-2
APPROX. 25 OHM NOW ?
NO YES
8 8
DIODE IS OK
DIODE IS DEFECTIVE
IS READING OK ?
SET OHM METER ON DIODE CHECK MODE
MEASURE DIODE RESISTANCE :
PLACE (+) LEAD ON ANODE AND (-) LEAD ON HEATSINK
READING SHOULD BE APPROX. 300 TO 800 OHMS
PLACE (-) LEAD ON ANODE AND (+) LEAD ON HEATSINK
READING SHOULD BE OPEN.