Lincoln Electric NA-5NF, NA-5SF service manual Test for AC supply to the speed- meter PC board

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F-68 TROUBLESHOOTING & REPAIR F-68

METER CIRCUIT ACCURACY TEST (Continued)

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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.

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.

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TP4

TP5

602510P

601 510

NA5 SPEED METER L6233

FIGURE F.10 SPEEDMETER PC BOARD AND TEST POINTS

NA-5