Lincoln Electric Fleet 650 Service Manual page 43

LINCOLN ELECTRIC
8. Check for grounds by placing one of the ohmmeter probes on a clean, unpainted metal surface of
the machine. Touch the other probe to each of the five rectifier terminals. The resistance to chassis
ground from each terminal should be very high, 500,000 (500K) ohms minimum. If the resistance
reading is less than specified, the rectifier is grounded and should be replaced.
9. If using diode checker or a multi-meter with diode check functionality, read and understand the
instructions that accompany your test equipment.
10. Using the appropriate volt/ohmmeter, perform the tests outlined in Table F.3. See Figure F.12. See
Wiring Diagram.
11. If any tests fail, the output rectifier bridge may be faulty.
12. If faulty, perform the Output Rectifier Bridge Removal And Replacement Procedure.
13. When testing is complete, reconnect all previously disconnected leads to the output rectifier bridge.
14. Perform the Case Cover Replacement Procedure.
TEST POINT (+)
AC TERMINAL 1
AC TERMINAL 2
AC TERMINAL 3
NEGATIVE DC TERMINAL
NEGATIVE DC TERMINAL
NEGATIVE DC TERMINAL
AC TERMINAL 1
AC TERMINAL 2
AC TERMINAL 3
POSITIVE DC TERMINAL
POSITIVE DC TERMINAL
POSITIVE DC TERMINAL
Table F.3 – Output rectifier bridge diode tests
TEST POINT (–)
POSITIVE DC TERMINAL
POSITIVE DC TERMINAL
POSITIVE DC TERMINAL
AC TERMINAL 1
AC TERMINAL 2
AC TERMINAL 3
NEGATIVE DC TERMINAL
NEGATIVE DC TERMINAL
NEGATIVE DC TERMINAL
AC TERMINAL 1
AC TERMINAL 1
AC TERMINAL 1
Fleet™ 650 Service Manual
DIODE BIAS AND EXPECTED
RESULT
0.3VDC - 0.7VDC
0.3VDC - 0.7VDC
0.3VDC - 0.7VDC
0.3VDC - 0.7VDC
0.3VDC - 0.7VDC
0.3VDC - 0.7VDC
OL
OL
OL
OL
OL
OL
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