Diagnostic Chart - Craftsman 139.53920DM Owner's Manual

Bell Wire
Diagnostic Chart
Safety Reversing
Sensors
Safety reversingsensorswire
open(broken or
disconnected).
OR
Safety reversingsensorswire
shortedor black/whitewire
reversed.
Door controlor wire shorted.
Safety reversingsensors
slightly misaligned
(dim or flashingLED).
Motor overheatedor possible
RPM sensorfailure. Unplug
to reset.
Motor CircuitFailure.
ReplaceReceiver
LogicBoard.
I 1
Your garage door opener is programmed with self-diagnostic
capabilities. The "Learn" button/diagnostic LED will flash a number of
times then pause signifying it has found a potential issue. Consult
Diagnostic Chart below.
• Symptom:One or both of the Indicator fights on the safety reversingsensorsdo not glow
steady.
• Inspect sensor wires for a short (staple in wire), correct wiring polarity (black/white wires
reversed), broken or disconnected wires, replace/attachas needed.
• Disconnect all wires from back of motor unit.
• Remove sensors from brackets and shorten sensor wires to 1-2 ft (30-60 cm) from back of
each sensor.
• Reattach sending eye to motor unit using shortened wires. If sending eye indicator light glows
steadily, attach the receiving eye.
• Align sensors, if the indicator lights glow replacethe wires for the sensors. If the sensor
indicator lights do not light, replacethe safety reversing sensors.
-• Symptom:LEDis not lit on doorcontrol.
• Inspect door control/wires for a short (staple in wire), replaceas needed.
• Disconnect wires at door control, touch wires together. If motor unit activates, replacedoor
control.
• If motor unit does not activate, disconnect door control wires from motor unit. Momentarily
short across red and white terminals with jumper wire. If motor unit activates, replace door
control wires.
-• Symptom:Sendingindicatorfight glowssteadily, receiving indicatorfight is dim or flashing.
• Realign receiving eye sensor, clean lens and secure brackets.
• Verify door track is firmly secured to wall and does not move.
-• Symptom:Motor has overheated;the motorunit does not operate or trolley is stuckon stop
bolt = Motor unit hums briefly; RPM Sensor= Shorttravel 6-8" (15-20 cm).
• Unplug unit to reset. Try to operate motor unit, check diagnostic code.
• If it is still flashing 5 times and motor unit moves 6-8" (15-20 cm), replace RPM sensor.
• If motor unit doesn't operate, motor unit is overheated.Wait 30 minutes and retry. If motor
unit still will not operate replace logic board.
...... • Symptom:Motor unit doesn'toperate.
• Replace logic board because motor rarely fails.
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