Lincoln Electric NA-5N Service Manual page 121

F-68
METER CIRCUIT ACCURACY TEST
9. Locate the speedmeter PC board.
See Figure F.10
10. Apply input power to the NA-5.
11. Test for AC supply to the speed-
meter PC board.
• Check for 8 to 11VAC from lead
#601 ot #602. See Figure F.10
Note: The coating will have to be
removed from the test points to ensure
accurate voltmeter readings. If the cor-
rect AC voltage is not present check for
loose or faulty connects with the associ-
ated leads. See wiring diagram.
FIGURE F.10 SPEEDMETER PC BOARD AND TEST POINTS
TROUBLESHOOTING & REPAIR
TP4
510P
602
601
510
NA5 SPEED METER L6233
NA-5
(Continued)
12. Test for DC volts on the speed-
meter PC board.
• Check for 4.75 to 5.25VDC from
TP5 to lead #510P. See Figure
F.10
Note: The coating will have to be
removed from the test points to ensure
accurate meter readings.
• If the display is NOT lit and the
correct DC voltage is present at
TP5 to lead #510P, the digital
meter may be faulty. Replace the
meter.
• If the AC voltage IS present at
leads #601 to #602 and the DC
voltage is missing, the speedme-
ter PC board may be faulty.
TP5
F-68