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Craftsman 1/2 H/P Garage door starts down, then goes back up

Posted by kywingnut (My Page) on
Mon, Aug 29, 11 at 18:24

Hi

I have a Craftsman Garage door opener, 1/2 HP chain drive. It's approx 4-5 years old.
The problem that I am having is it starts down, then after about a foot, it goes back up.
I have checked the photo eyes and they look fine, no blinking lights. Even if I hold the button down, the garage door returns up after a foot or so.
If I dis-connect the door from the chain, it still does the same thing.
Manually, I can raise and lower the door without any problems.
I get 5 blinking lights after the door returns back up.
I bought a used RPM sensor off of ebay ( I actually received 2). I tried both of those and still had the same problem.
I could buy a new sensor, but the person I bought the used sensor off, says they are good and he has 100% positive feedback, so I believe they are good.

Any other ideas? I am stuck. Any help would be appreciated.
Thanks in advance!
Mike

Any


Follow-Up Postings:

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RE: Craftsman 1/2 H/P Garage door starts down, then goes back up

If when the door reverses to the open position the main light flashes 10 times it is a door sensor problem. Make sure both small lights are on and not flickering ever so slightly. (check closely) Tweak them a little. Check for 5vdc between terminals 2 and 3 on the rear of the motor unit. If there is no voltage or if it is greater than 6 vdc the logic board is bad.


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RE: Craftsman 1/2 H/P Garage door starts down, then goes back up

Thanks for your fast reply Don. I thought by pressing the close button down continuously, that that basically bypassed the sensors. I will definitely run those checks on the sensors tomorrow after I get home from work.
Thanks again!


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RE: Craftsman 1/2 H/P Garage door starts down, then goes back up

Well, I checked the sensors and they seem to be lined up and mounted firm. Both lights are on solid with no flicker.
I checked voltage between terminals 2 and 3 and got 5.9 vdc.
I'm not sure what to look at next. Any other thoughts?
Thanks again.
Mike


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RE: Craftsman 1/2 H/P Garage door starts down, then goes back up

What puzzles me is you say you get 5 blinking lights when the door goes back up. Are you sure it is 5 and are you talking about the main light - not an LED? Are you sure you put the black plastic cup back on the end of the motor shaft after changing the RPM sensor board? Make sure it is pressed all the way on. Release the door from the opener and see if there is any binding as you lower and open it.


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RE: Craftsman 1/2 H/P Garage door starts down, then goes back up

Don, thanks for your reply.

I definitely have the black plastic cup on and it's pressed all the way on.

The little yellow led in the back by the red button and the terminal screws 1,2,3 flashes 5 times, pauses then flashes 5 again.

The main light just turns on when I try to lower the door, it doesn't blink , flash or anything. Just stays on for a bit, and if I don't try to lower the door again, it will shut off.

Do you think I got a bad rpm sensor? The guy sent me 2 of them and I tried them both. I did keep my original cap on though, I figured that would still be good

Thanks, Mike


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RE: Craftsman 1/2 H/P Garage door starts down, then goes back up

I've never done this, but I've read that you can short some of the wires on the light sensors to make them think there's always a good light connection. Obviously this isn't recommened as a long term solution, but to test whethter or not the lights are the issue, it might help. I don't have the details and it may only work for certain models, but google is a good source of information.


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RE: Craftsman 1/2 H/P Garage door starts down, then goes back up

The LED flashing 5 times is sending the code for RPM sensor or motor overload. The motor is running so you can forget the overload bit. I'm a little leery of you getting 2 bad RPM sensors but that is always a possibility when dealing with e-bay and used parts. If you can, watch the motor when it starts to run. Make sure the shaft is not moving so far that the plastic cup is moving from between the infra-red eyes on the RPM sensor.

FYI there is no way to bypass or defeat the door sensors no matter what you might read on google as kidhorn says.


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