Lynx Pro GDO won't close

[euchretobin]

This is a 1/2 HP chain drive opener that recently started refusing to close reliably. Symptoms are:

• Door begins to close, after ~2 to 5 feet of travel it reverses and the light blinks as if an obstacle were encountered. The "trouble spot" is not consistent run to run.
• Disconnecting door from the carriage makes no difference. This made me suspect the chain and track (see below). By hand the door travels easily.
• I can make the door close by hitting the switch quickly after a reverse (which stops it), and hitting again to resume the close. Sometimes this only takes 3 iterations. Sometimes well more than 10.
• It seems worse in colder temperatures.

So far I have:

• Greased the chain
• Tried increased and decreased chain tension
• Lubricated the door rollers
• Felt along and visually inspected the chain guide for obstacles
• Increased and decreased closing force to the extremes
• Greased the internal drive gears
• Verified that the limit contacts are placed appropriately and working
• Checked sensor alignment and verified they work

Either it's something simple I've not thought of, or something complex like ckt problems on the logic board or the "flywheel strobe" sensor that I'm guessing checks for closing resistance. Any ideas or suggestions for further checks?

Thanks! -Paul

[Harold14370]

Paul,
This worked for my Craftsman GDO. I simply used a screwdriver to tighten the terminal screws where the electric eye sensors connect on the motor housing.

The theory behind it is this. When the motor is not running, your sensors work fine. With the motor running, the loose electrical connections cause a noisy signal, which triggers the GDO to reverse.

[RandomIan]

This is a 1/2 HP chain drive opener that recently started refusing to close reliably. Symptoms are:

• Door begins to close, after ~2 to 5 feet of travel it reverses and the light blinks as if an obstacle were encountered. The "trouble spot" is not consistent run to run.
• Disconnecting door from the carriage makes no difference. This made me suspect the chain and track (see below). By hand the door travels easily.
• I can make the door close by hitting the switch quickly after a reverse (which stops it), and hitting again to resume the close. Sometimes this only takes 3 iterations. Sometimes well more than 10.
• It seems worse in colder temperatures.

So far I have:

• Greased the chain
• Tried increased and decreased chain tension
• Lubricated the door rollers
• Felt along and visually inspected the chain guide for obstacles
• Increased and decreased closing force to the extremes
• Greased the internal drive gears
• Verified that the limit contacts are placed appropriately and working
• Checked sensor alignment and verified they work

Either it's something simple I've not thought of, or something complex like ckt problems on the logic board or the "flywheel strobe" sensor that I'm guessing checks for closing resistance. Any ideas or suggestions for further checks?

Thanks! -Paul

Sounds like it might need a new Circuit Board, quickest and easiest repair, the other option is to replace the unit.

CHEERS

-Ian

[gdoorpro]

chamberlain diagnostic chart

Have you verified that the wiring to the photo-eyes is not pinched or cut. This could be anywhere. If the receiving eye blinks or even flickers for just a millisecond this will cause a problem.

I would be hesitant to replace a circuit board when you can upgrade to a belt drive unit for twice as much money. You should check the diagnostic light assuming you have a Chamberlain operator (Craftsman, LiftMaster, of Chamberlain brands) This is found near the learn button. The number of times it blinks will tell you what may or may not be wrong.


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.
Diagnostic Chart

1 Flash
Safety reversing sensors
wire open (broken or
disconnected).
or 2 Flashes
Safety reversing sensors
wire shorted or
black/white wire reversed.

Symptom:One or both of the Indicator lights on the safety sensors do
not glow steady.
• Inspect sensor wires for a short (staple in wire), correct wiring polarity
(black/white wires reversed), broken or disconnected wires, replace/attach
as 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 each of 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 replace the wires for the sensors. If
the sensor indicator lights do not light, replace the safety sensors.

3 Flashes
Door control or wire shorted -

Symptom:LED is not lit on door control.
• Inspect door control/wires for a short (staple in wire), replace as needed.
• Disconnect wires at door control, touch wires together. If motor unit activates,
replace door 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.

4 Flashes
(Safety reversing sensors
slightly misaligned
(dim or flashing LED).

Symptom:Sending indicator light glows steadily,receiving indicator light
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.

5 Flashes-
Motor overheated or
possible RPM sensor
failure.Unplug to reset.

Symptom:Motor has over heated;the motor unit does not operate or
trolley is stuck on stop bolt = Motor unit hums briefly;RPM Sensor =
Short travel 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.

6 Flashes
Motor Circuit Failure.
Replace Receiver
Logic Board.

Symptom:Motor unit doesn’t operate.
• Replace logic board because motor rarely fails.

[Brian Michael]

quote on logic board

41A4 315-7c sears GDO with 1/2 HP motor. flashing 5 times. unplug and replug in no help. When on/off switch pushed, a click is heard, but no motor action. Can you give me a quote on a new board? Thanks Brian

Have you verified that the wiring to the photo-eyes is not pinched or cut. This could be anywhere. If the receiving eye blinks or even flickers for just a millisecond this will cause a problem.

I would be hesitant to replace a circuit board when you can upgrade to a belt drive unit for twice as much money. You should check the diagnostic light assuming you have a Chamberlain operator (Craftsman, LiftMaster, of Chamberlain brands) This is found near the learn button. The number of times it blinks will tell you what may or may not be wrong.


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.
Diagnostic Chart

1 Flash
Safety reversing sensors
wire open (broken or
disconnected).
or 2 Flashes
Safety reversing sensors
wire shorted or
black/white wire reversed.

Symptom:One or both of the Indicator lights on the safety sensors do
not glow steady.
• Inspect sensor wires for a short (staple in wire), correct wiring polarity
(black/white wires reversed), broken or disconnected wires, replace/attach
as 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 each of 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 replace the wires for the sensors. If
the sensor indicator lights do not light, replace the safety sensors.

3 Flashes
Door control or wire shorted -

Symptom:LED is not lit on door control.
• Inspect door control/wires for a short (staple in wire), replace as needed.
• Disconnect wires at door control, touch wires together. If motor unit activates,
replace door 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.

4 Flashes
(Safety reversing sensors
slightly misaligned
(dim or flashing LED).

Symptom:Sending indicator light glows steadily,receiving indicator light
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.

5 Flashes-
Motor overheated or
possible RPM sensor
failure.Unplug to reset.

Symptom:Motor has over heated;the motor unit does not operate or
trolley is stuck on stop bolt = Motor unit hums briefly;RPM Sensor =
Short travel 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.

6 Flashes
Motor Circuit Failure.
Replace Receiver
Logic Board.

Symptom:Motor unit doesn’t operate.
• Replace logic board because motor rarely fails.

[gdoorpro]

a new board will probably run you about $100. You can call a sears service center for an exact price. Otherwise i would need to know a little more info. It is not that old since it has the 315mHz frequency, so a board replacement is the best way to fix. Installed I usually charge around $160.

If you call the service center, or the number on the manual, give them your model number. Sears has rather long model numbers. but they have so many different styles of boards that would work with different models, but wont fit in the slots of all openers.

you can find my email under my profile.

Ryan