Most helpful customer reviews
42 of 43 people found the following review helpful.
TRY THIS BEFORE YOU BUY IT
By Mr. Hytech
FYI: You may not need to buy this at all - you might be able to solve your problem by trying this...
HOW IT WORKS: This is simply a sensor module that consists of an LED that shines a small beam of infrared light across a small gap to a phototransistor (the module is the black object on the circuit board). The fins on the plastic pinwheel interrupt that beam of light as it spins on the motor shaft. That generates pulses that tell the control board that the motor is spinning. Since these kind of modules virtually never fail, it is likely that the pinwheel has slid out of alignment with the sensor. Make sure the 5 flaps on the wheel penetrate around 1/4 to 3/8" into the gap of the sensor - without hitting anything of course. This can be accomplished by sliding the pinwheel on the shaft closer to the motor. It may take a small amount of gentle force to slide it, but that should fix the 6-8 second run / stop / reverse symptom. You can ignore the 2 stars - I had to click on something to get the attention of the techies who might want to look into a reason for not buying it. They may not have to. My apologies to Amazon if this prevents any sales, but I give Amazon 5 stars for this feedback system.
12 of 12 people found the following review helpful.
saved me $91. yay!
By George P.
so, i have a 1/2 hp craftsman garage door that worked for everyone with no problems except me. Every time i was trying to close it, it would start closing and after 8-10" of travel, it would go back up and start clicking. I'd try it again and it would do the same - start to close, then stop and go back up, and clicks...
so, i called a garage door repair dude, he came over and said "it's the RMP sensor". I will fix it for $100. let me know when you want to do it".
His mistake was to tell a guy who is really handy what is causing the problem. I came on amazon, purchased the RPM sensor, took the cover off, unplugged the old sensor, plugged the new sensor and the door works like a charm right now. his price - $100. my cost - $8.99 + S&H + 15 mins of labor. the 500 screws that were holding the cover took more time than the actual repair.
apparently liftmaster makes the RPM sensors for craftsman. in fact, craftsman is exactly the same product as lift master. they just get to charge more.
so, there you have it. if you door can't open or close all the way down, get one of these and save a bunch of money.
7 of 7 people found the following review helpful. See all 96 customer reviews...
RPM sensor and motor shaft movement
By Richard C. Bejtlich
In my experience with two different garage door openers, one a Craftsman and the other a Liftmaster, both had the same problem of starting to close then reversing after only going a few inches. It turns out that the RPM sensor was NOT bad but the in and out loose movement of the motor shaft was causing the sensor to give bad signals to the control board. All that was needed was to loosen the Allen head set screw on the motor shaft collar behind the sensor, pull the shaft forward (toward the track) as much you can, slide the collar over and tighten the set screw. The motor shaft can also be pushed on the opposite end of the motor also. Make sure that the plastic interrupter cup on the end of the shaft is also pushed on the shaft securely. Also, sometimes dust can collect on the sensor so blowing this out might be necessary too. It appears the tangs on the plastic cup assembly function to interrupt a photoelectric beam on the RPM sensor card as the shaft rotates. The bottom line- check the motor shaft before buying a new sensor!