Lincoln Electric LN-25 Service Manual page 59

F-21
HALL EFFECT MODULE TEST (continued)
FIGURE F.11 CONTROL PC BOARD (CODES ABOVE 10500)
J1
4. Apply at least 25 VDC but no more than 100
VDC to the LN-25™ from the electrode cable to
the work sensing lead. Observe polarity and set
polarity switch.
5. Check for the presence of 12 VDC from lead
512(+) to lead 500(-). If the 12 VDC is not
present or low, the control board may be faulty.
See Figure F.11or F.11.a.
6.Activate the LN-25™ trigger circuit, make sure the
drive motor is running and check for the
presence of approximately 6.0 VDC from lead
555(+) to lead 500(-). The value of 6.0 VDC
FIGURE F.11.a CONTROL PC BOARD (CODES ABOVE 10500)
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TROUBLESHOOTING AND REPAIR
J3
667
621
J1
J3
555
J4
500 512
represents the correct feedback voltage from
the hall effect device to the control board.
7. If the above voltage reading is not correct, the
hall effect device may need to be adjusted (see
the Maintenance Section) or replaced. See the
Drive Motor and Gearbox Replacement and
Access to Hall Effect Module procedure.
NOTE:Machines with L12253-[ ] PC Boards react
differently to loss of feedback. Instead of
running full speed, the motor voltage is
held to approximately 14VDC.
555
J4
512 Contactor
500
LN-25™
G3425
J2
691
J14
J2
690
F-21