Sears Garage Door Opener/ problem closing door

Posted by James on January 16, 2009, 4:39 pm

I have an older , Sears, chain operated garage door opener. Mechanically,
the door is working fine, but I have a problem with the two safety sensors
that beam a light across the bottom edge of the door, about 5 inches off the
floor bottom.

The door will open fine, but will not close. I am 99% sure the problem is
in the two sensors just described.

On one of the sensors, which I think is the sending unit, the little pilot
led light is bright and pretty. However, on the other unit, which is
marked the "Receptor" unit, the small led light is barely, barely, lit.
It is getting voltage, as the led pilot light will very faintly light up
when I apply the electrical wiring plug into it. I can also tell that when
I line up the two sensors, and then place my hand across the beam of light,
I can just barely detect that it faintly changes the intensity of the led
pilot light.

My suspicion is that this "Receptor" unit has gone bad.

Two Questions please:

1. Am I on the right track ?

2. Can these sensors be bought at Lowe's or Home Depot ?

---------------

Any comments or input would be very much appreciated.

Thank you very much !!

James

Posted by PeterD on January 16, 2009, 5:32 pm

wrote:

>I have an older , Sears, chain operated garage door opener.

How old... Model?

>Mechanically,
>the door is working fine, but I have a problem with the two safety sensors
>that beam a light across the bottom edge of the door, about 5 inches off the
>floor bottom.
>The door will open fine, but will not close. I am 99% sure the problem is
>in the two sensors just described.
>On one of the sensors, which I think is the sending unit, the little pilot
>led light is bright and pretty. However, on the other unit, which is
>marked the "Receptor" unit, the small led light is barely, barely, lit.
>It is getting voltage, as the led pilot light will very faintly light up
>when I apply the electrical wiring plug into it.

Interesting. At least on mine, the lamp's brightness is directly
related to the transmitter's light that it receives. Are you sure that
the lenses are clean on both units (no cobwebs, crud, or other stuff
there) and that they are properly aligned.

> I can also tell that when
>I line up the two sensors, and then place my hand across the beam of light,
>I can just barely detect that it faintly changes the intensity of the led
>pilot light.
>My suspicion is that this "Receptor" unit has gone bad.

There is no way without measuring the light output of the transmitting
one to determine that.

>Two Questions please:
>1. Am I on the right track ?

Maybe. Does the door not even try to close? Or does it get part way
down, then reverse?

>2. Can these sensors be bought at Lowe's or Home Depot ?

I don't think so, but it is possible. I've seen some parts at both
stores that I'd not have thought the'd have carried.

>---------------
>Any comments or input would be very much appreciated.
>Thank you very much !!
>James

Check the light path, and make 100% certain that there is no dirt,
dust or crud partially blocking the lenses on either end.

Posted by James on January 16, 2009, 5:46 pm

thank you so much Peter. One thing you mentioned was to check the lens
cover on the Sending unit........ I had only checked the Receiver. I will
check the Sender tomorrow.

The door will start down, but after a bit it will reverse and go back up.
It will open fine. I can force it down by pushing the wall switch and
holding it until the door is fully closed.

I need to get the model number of the unit, and will post it. I do know
that it is quite old............

Thanks again.

James

Posted by PeterD on January 17, 2009, 9:48 am

wrote:

>thank you so much Peter. One thing you mentioned was to check the lens
>cover on the Sending unit........ I had only checked the Receiver. I will
>check the Sender tomorrow.
>The door will start down, but after a bit it will reverse and go back up.

OK, this sounds exactly like the force seensor is tripping. This is a
sensor that monitors the motor's current, when it sees a rise in
current above an acceptable predetermined limit, it reverses the door
thinking that the door is blocked. This is doen because it is possible
to have a car in the doorway but because of the wheels holding it (the
car) above the sensor light beam, the light won't be blocked.

If the light sensor is not working the door will not even start down
on most models.

>It will open fine. I can force it down by pushing the wall switch and
>holding it until the door is fully closed.
>I need to get the model number of the unit, and will post it. I do know
>that it is quite old............

'quite old' is a broad range! What I call old, some people think of as
relatively new. And I've seen stuff that was described as old, and I
figured it was relatively new! See if you can find a date code on the
label...

>Thanks again.
>James

Posted by jamesgangnc on January 17, 2009, 10:26 am

Agreed. The fastest diagnosis for that is to uncouple the door and see how
hard it is to opena nd close by hand.

> wrote:

>>thank you so much Peter. One thing you mentioned was to check the lens
>>cover on the Sending unit........ I had only checked the Receiver. I
>>will
>>check the Sender tomorrow.
>>The door will start down, but after a bit it will reverse and go back up.

> OK, this sounds exactly like the force seensor is tripping. This is a
> sensor that monitors the motor's current, when it sees a rise in
> current above an acceptable predetermined limit, it reverses the door
> thinking that the door is blocked. This is doen because it is possible
> to have a car in the doorway but because of the wheels holding it (the
> car) above the sensor light beam, the light won't be blocked.
> If the light sensor is not working the door will not even start down
> on most models.

>>It will open fine. I can force it down by pushing the wall switch and
>>holding it until the door is fully closed.
>>I need to get the model number of the unit, and will post it. I do know
>>that it is quite old............

> 'quite old' is a broad range! What I call old, some people think of as
> relatively new. And I've seen stuff that was described as old, and I
> figured it was relatively new! See if you can find a date code on the
> label...

>>Thanks again.
>>James
>>

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