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Please begin with an informative title:

Happy Saturday morning, everyone, and welcome to the August 1st edition of SMHRB--the place where the DKos community mingles and lingers to discuss home repair, remodeling and related DIY activities. This is TerribleTom in my second attempt as a guest host.

[And speaking of guest hosting, I’d be remiss if I didn’t start by saying--for everyone I’m sure--that we’ve really been missing main dude Claude and hope that Evelette and Claude are doing well!]

So...walk right in, it’s around in back. Say hello to Alice, flop down on one of the home-made bean bag chairs, kick up your heels and don’t be shy about asking any questions you may have. Better yet, chime in with something you've learned from your own experiences, whether it is specifically related to this week’s topic or not.

Today’s topic is designed to get you coming and going: It’s living with garage door openers, or GDOs. As a relative newbie to this blogging forum, I hope I’m not covering too much old ground.

Intro

You must enter an Intro for your Diary Entry between 300 and 1150 characters long (that's approximately 50-175 words without any html or formatting markup).

I should apologize at the outset for the lack of pics or graphics in today’s SMHRB edition. The fact is, I had another topic planned but managed to leave my digital camera a few states away. So I’ll plunge right in with a fake question-and-answer format. (Fake because I chose questions I thought I’d have a reasonable chance of answering.)

Is one brand of garage door opener better than another?
While there may be some high-end deluxe equipment out there (I wouldn’t know from personal experience!), Sears commands a huge share of the market. Don’t like Sears? Well, if you buy a Chamberlain from Home Depot, it turns out that Chamberlain makes Sears so they’re essentially the same thing. Liftmaster is also made by Chamberlain. Genie, I believe, is the largest truly distinct competitor and is made by a different company, but I know of no reason to suspect they are significantly better or worse. YMMV.
Every once in a while, my garage door opens or shuts for no apparent reason. Could this be caused by poultergeists?
When you set up the remote codes, did you by any chance set it with all of the dip switches up...or down...or every other one up or down...or didn’t bother changing it from the factory settings? If so, and you have nearby neighbors with a garage door opener, there are probably two morans living on your street: you because you used such a simple code and one of your neighbors who did the same thing. :-) It happens.  

But seriously, the limited number of security codes used by old models with eight dip switches (only 256 possibilities!) can pose definite security vulnerabilities—especially when so-called weak codes are used.

But even with randomly chosen codes, the oldies are vulnerable. The bad guys, it seems, learned to use “sniffers” to surruptitiously read the code when someone pressed their remote. Another tactic was to set different codes (with the least creative tried first) and drive through neighborhoods trying to make doors open. It still happens from time to time.

As a countermeasure, remote technology has gone through several upgrades. The current technology of choice is known as “rolling code” and was introduced in the early 90s, although it took a while to phase in. It’s the same technology used with cars now and is quite difficult to thwart.

Where is the code set?
That depends. The first generation relied on the radio frequency alone. Once these became popular enough that it was likely there could be more than one on the same block, the problem of discriminating between your door and your neighbor’s became obvious—even comical at times.

Second-generation openers differentiate from one house to the next according to the code.  The same code is manually set by dip switches in the opener and the remote(s) and all openers of a model type use the same frequency for transmission.

In third-generation equipment, the code is manually set in the remote and, while following a procedure (typically holding a button down for a set amount of time), the opener reads the code from the remote.

In the fourth generation the remote has to learn from the opener how to communicate with it in a way that is cryptographically unique to that opener. The protocol uses a wider band of frequencies (300-400 MHz) and hops from one to another.  Furthermore, the transmitter and receiver renegotiate a new session code each time they are used, based on a so-called seed code. In effect they use a new code each time and are therefore immune from sniffing and duplicating the transmission from the last time the remote was used. If you like spook stuff, it’s pretty neat tech.

But, alas, problems arose due to interference with the army’s mobile communications systems, which also use frequencies in the 300-400 MHz range. So, in the fifth generation, the use of frequencies was cut back and standardizing at 315 MHz. Arguably, the newest remotes are less secure than the generation before them! But they are also less prone to interference from other stuff using a wider frequency band.

OK, enough of that techie stuff. Back to more practical matters.

I push the button and nothing happens--not even a faint click.
If you’ve tried both a remote and the wall-mounting doorbell-type button and there are no blinking signs of life, a good place to start is by making sure you have power. It’s like most things electrical—does the receptacle give juice to something known to work like a lamp or circuit tester?
The door won’t close. When the remote is pressed, the light may come on and the door might start downward, but it quickly “aborts the mission”.
The most likely cause is that the sensors are out of alignment.

Openers made since the early 90s have sensors placed near the bottom of the tracks on each side of the door. They function as “electric eyes” to ensure that the door path is clear before the door will close. (Some models, but not all, will still close if the hardwired “button” is held down instead of using the remote.)

For the doors to work, the sensors need to be pointed directly at each other. If they’re aligned correctly, a small light (usually green) on each side should be lit and not blinking or flickering. If they are cross-eyed, one or both of the lights may be dark or one may be green while the other is amber.

Of course, this may not be a problem at all. You may have something in the way that is blocking the light path between the sensors. If so, remove the obstruction--the sensors are just doing their job.

But if the path is clear but the lights aren’t green, then tinker with the alignment. Misalignment problems are among the commonest of GDO problems, as the sides of a garage door opening can be subject to all kinds of bumping around as garbage cans, lawn mowers, bicycles and such get trundled in and out of the garage.

If that doesn’t resolve the problem, it may be time to inspect the small-guage wire leading to the sensors to look for something that’s pulled loose or frayed or to get out a voltmeter and test the circuit. If the problem turns out to be the sensors themselves, a new sensor kit can be purchased from the brand’s parts dealer for $35-40 and isn’t too difficult to replace. (If the unit is getting old, however, replacing the whole unit may be the better choice.)  

The door stops opening or closing somewhere in the middle of its path.
Start by unhooking the door from the trolly mechanism. (Most models have a quick release mechanism with handle and cord.) Then work the door up and down manually to make sure it’s free along the run. About halfway between fully open and closed you should discover a balance point where it will neither fall nor continue going up. The door should feel “square”—that is, neither side wants to go up or down more than the other and it doesn’t want to move in a cockeyed direction. (Remember: the springs do most of the heavy lifting, not the motor!)

If it doesn’t have a good and square balance point, you may need to have a professional adjust the springs.

BIG CAUTION: Adjusting springs is potentially very dangerous if you’re not trained to do it. While doors with the two long springs that run in parallel on both sides of the tracks may not be quite as dangerous as the ones with a horizontal coil on a shaft mounted on the header of the door, I don’t recommend undertaking spring adjustments as a DIY project. You can get thrown into the next county or even killed messing with the wound-up coil type!

Assuming the door is balanced, close it and initiate an open/close cycle with the trolly still unconnected from the door. That’s a check to ensure that the chain or trolly isn’t bound up or jammed somewhere. If that doesn’t work, there’s probably a problem with the logic board, motor or some other mechanical problem such as with the gearing or sprocket. (You might be looking at a new opener, groan.)

Once you’ve verified that the door and the trolly operate OK independently, try increasing the downward force adjustment a bit. I list this last because it’s better to rule out spring problems and mechanical obstructions before upping the brute force.
 

I programmed a second remote and now the first one won’t work.
If your GDO is of an older type where you program the remote and then have the opener “read” the code (by holding a button while this occurs), you’ve changed the code in the receiver to a new code, so your first remote is out of sync. If you have rolling code technology, the old remote may have to renegotiate the protocol. (It's in the manual!)
Is this the only problem that could cause that?
Sadly, no. It’s getting a whole lot more complicated out there each year. As manufacturers migrated toward the enhanced security features of “rolling code”, they built in support for older technologies (e.g., so-called “billion code”) as well as different frequency bands. Under some circumstances, devices can revert automagically to “old technology” or old frequency bands. But that doesn’t mean everything necessarily reverts at the same time. Thus, your remote may have reverted while your keypad thinks it’s living in the modern era...and so forth. While the logic board can operate on more than one technology, it can’t operate on both at the same time.

It’s beyond the scope of this diary to try to cover the permutations of ways this can get out of whack, but suffice it to say that it can be perplexing and maddening. The best advice for this-works-and-that-doesn’t type problems with multiple remotes and/or keypads, is to get out the manual, go back to square one and reprogram everything, resetting everything to known values. There comes a point at which trying to figure it out is likely to drive you nuts.

A related tip: If you need to buy a new remote, it is very important to match technologies--moreso even than brand name.

What does it mean when a red led light blinks five times...or three times.
It means you need to RTFM (thanks for that, Code Talker). Geez, you expect me to know that off the top of my head...for all models? The manuals for GDOs really are something you should put somewhere you can find them because some of the diagnostics are not intuitive at all, and if you aren’t servicing GDOs all the time, most of us will need to look them up. For current or recent models sold by Sears, you may be able to find the manual in PDF form by searching sears.com.
I followed the diagnostics in the manual and it seems I have a faulty logic board. Is this something a reasonably competent DIYer can handle?
Yes. It’s the troubleshooting that’s the challenge. (Oh, and maybe locating the right part.) But the swap-out is quite easy on the common models. Make sure the power’s off (i.e., pull the plug, DOH!), remove a couple of screws and the cover, pop out the old board and plug in the new.

OK, I think that’s about enough about GDOs. Besides, it’s pretty close to all I know on the subject.

Your turn...

Extended (Optional)

Originally posted to SMHRB on Sat Aug 01, 2009 at 05:59 AM PDT.

Poll

Just curious: have you ever had to fix/replace a GDO?

51%19 votes
13%5 votes
35%13 votes

| 37 votes | Vote | Results

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