L-852A-D, J & K ITCF, F-Range, ICAO LED Taxiway Centerline Light
96A0460 Rev. C
Maintenance
© ADB Airfield Solutions All Rights Reserved
22
2.4.2.4 Testing an LED
assembly
For this test, use a Fluke 87 or equivalent meter.
A “Diode Test” function may be used as a quick pass/fail check on one or two LEDs. In the
maintenance shop, open the fixture and unplug the LED assembly.
1. Set the meter to test a DIODE.
2. Connect the meter leads to the LED assembly. Observe if the LEDs glow and also note
the meter reading of the LEDs.
3. Then reverse the meter leads and observe the LEDs again.
NOTE:
With good LEDs when forward biased, the LEDs will glow dimly and the meter will
indicate a low resistance. When the LEDs are reverse biased, the LEDs will not glow and the
meter will indicate a high resistance.
4. Test a known, good LED assembly in the same manner to verify your meter’s operation
and typical meter indications.
Figure 13:
Diode testing an LED assembly with a Fluke 87 Meter
CAUTION
Do no use the megger function or a resistive test of any meter on an LED assembly! This may
damage the LED’s properties required for proper operation.
This test only works for LED light engines of one or two LEDs. If three or more LEDs are present
in the light engine, a different testing method is required which is not covered here.
these instruction can result in equipment damage.
Low meter reading
Meter on Diode Test
Dim but Glowing LED
Correct polarity
(forward Bias)
red to red,
black to black.
