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Craftsman 1/2 hp Garage Door Opener Problem

Posted by bill_911 (My Page) on
Fri, May 4, 07 at 17:31

Hello to the forum. Hopefully someone can help me with this problem. Craftsman model 139.53635SRT1. The unit is probably 8-9 years old. For the most part, it's been a good unit. It ignores the up-limit switch once or twice a year and jams against the safety bolt, but that is easily correctable....and I've replaced the plastic drive gears once....but otherwise it just worked like it should over the years. All of a sudden however, it doesn't want to open or close reliably.

Symptom #1: Sometimes when I try to close the door from the fully up position, it moves the door down maybe a foot or so, and then reverses it back up a small amount and stops. It acts is if it is sensing something in the down path and reacting accordingly.....but the light on the front of the main control unit does NOT flash when this problem occurs. If I hit the wall button and stop the door just as it wants to start back up, I can get the door to stay in place. When I push the wall button again, the door will again start down, but only travel a foot or so, and then go back up a short way and stop. If I repeat the above process over and over, I can make the door close completly a little bit at a time. When trying to close the door, if I push and HOLD the wall switch, the door will fully close as it should. (Makes me think a sensor problem....but why doesn't the light on the front of the control unit flash off and on)? (Also see later on for more info on the sensors).

Symptom #2: Sometimes when I try to open the door, the door will move up only a small amount and then reverse a small amount and stop....kind of like Symptom #1, but in reverse.

Now for some additional information. First of all, sometimes the opener works correctly, opening and closing the door as it should. Sometimes I can make the problems go away by unplugging and plugging it the control unit....but sometimes not. Sometimes the problems just go away on their own. When the problems do occur, it is not a physical problem with the door itself. The symptoms occur even with the door disconnected and the trolly moving freely on the rail. At no time does the main light on the control unit flash on and off. Both the emitter and receiver LED's in the safety sensors are a steady bright green. I have realigned the sensors with no effect on the problem. I have also verified all wiring between the sensors and control unit with an ohmmeter plus I stripped and reattached the wires at the control unit with no effect on the problem. I have disconnected and reconnected the connectors to the limit switch assy and the logic board with no effect on the problem. One final note, the indicator LED on the logic board usually blinks five times over and over when the problems occur.

I'm thinking the logic board is probably going bad....but maybe someone else can offer some advise? Please?? How about it Don or GDS if you're out there? You guys certainly seem to know what you're talking about. Any help from anyone will be greatly appreciated! Thanks in advance!


Follow-Up Postings:

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RE: Craftsman 1/2 hp Garage Door Opener Problem

I think the code you are getting from the LED is the clue. That code is "RPM sensor or motor overload." A bad RPM sensor will give the symptoms you describe. It is the small PC board on the door side of the motor. It has 4 wires connected to it by a quick disconnect. Let us know how you make out.


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RE: Craftsman 1/2 hp Garage Door Opener Problem

BINGO! Close examination of the RPM sensor circuit board showed that the little LED emitter/receiver unit was loose on the circuit board. I'm guessing the vibration of the opener would cause the internal wiring of the LED unit to either make a connection to the board or not. A little super glue tacked the LED unit tight to the board and the opener is now working just fine! If the problem comes back I'll replace the RPM sensor but for now all appears to be well. Thanks so much for your help!


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RE: Craftsman 1/2 hp Garage Door Opener Problem

'96 Craftsman 139 53648SRT model

1) problems closing....go down a lil a come back up. RPM sensor I suspect ???

2) LED flashing 5 times.....RPM sensor ?

3) while researching above problems...now when the remote or wall unit (no pad) is engaged, there is nothing but a slight/quick "humming" noise..and nothing happens. This is a new symptom.

4) I have checked/tired to align the infra red sensors.... this model has both lights on constant, regardless of whether they are in sync or not. I checked the wiring from teh sensors back to the motor/unit. I'm not sure how to align them now.

QUESTIONS: which do I address first ? I'm not sure I can align the infra red sensors without the "humming" and no activity when I engage the opener. Should I look at the RPM sensor first ? Is the gear stripped ??? causing the humming and non activity ? The opener was opening before I started working on it.

Thanks to anyone and everyone who has advice on this.


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RE: Craftsman 1/2 hp Garage Door Opener Problem

Don I am having the same issue as bill_911 but if I play with the cup assembly it will open all the way but still will not close. I also noticed that the cup assembly is cutting into the RPM sensor board don't know if that will cause any thing.

my senors are aligned and this happens when door is not connected to opener. It just started to do this a couple days ago.

thanks don


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RE: Craftsman 1/2 hp Garage Door Opener Problem

Don I am having the same issue as bill_911 but if I play with the cup assembly it will open all the way but still will not close. I also noticed that the cup assembly is cutting into the RPM sensor board don't know if that will cause any thing.

my senors are aligned and this happens when door is not connected to opener. It just started to do this a couple days ago.

thanks don


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