? about garage door opener

These openers are very cheap to buy, and are not considered serviceable. The only thing you can check are the battery contacts, and see if there are any cold solder connections.

Many of these openers, depending on the country of use, are working in the

512, 310, 410, or in the 427 mHz range. In different countries, there may be different frequencies allocated for these. There are some new systems coming out that will be using Bluetooth, which is in the 2.4 to 2.5 gHz range. The older systems from before the 1970's were working in the 27 mHz range.

They consist basically of a digital code generator, and a simple transmitter circuit. The output is of AM modulation in the lower cost systems. The more expensive remote systems are using spread spectrum technology, so that the codes would be much more difficult to read remotely.

The power output is usually in the area of about 10 to 20 mW. The range is designed for about 50 to 75 feet operation.

--

Jerry G.
==========================


"Dave"  wrote in message
news:ch87iq$dt5@library1.airnews.net...
Mother-in-law has a garage door opener activator (what do you call the thing
with the button, that you carry in the car, anyway?) which has apparently
gone south.  I promised to take apart and try to find the problem, or prove
that the activator is at fault.  Any ideas on what these things send out?
No idea what I am looking for...

Thanks,

Dave (who has an O-scope, freq counter and multimeter.)
db5151@hotmail.com

Thanks for the reply, Jerry.

I'm in the US, and this is just a regular Genie (I think) garage door opener from about 10 years ago, so I doubt if there's any bluetooth technology involved. I opened it up last night and there are just a few components, mainly one 8 pin dip chip (didn't notice the number) and a diode alone with a couple capacitors and a few resistors (and a small coil antenna). Shouldn't be too much to deal with. It will at least give me something to tinker with. I'll hook it up to the scope, and see what I see.

Any other input is welcome.

Dave snipped-for-privacy@hotmail.com

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These are usually simple RF transmitters that send an encoded signal (digital word) to the receiver. I recently fixed a older Craftsman that the only available remote was on the wrong frequency 168megs as I remember. I required a converter from Sears ~ $60 to put it on frequency. I just opened it up and adjusted the tank circuit to the frequency. Works fine.

If your O-scope is sensitive enough at this frequency you might see the RF output. Even if it isn't you might see it enough for a go no go. If you can get your hands on a similar transmitter you might be able to change the code (usually a series of DIP switches inside the xmitter) to test if it's the xmitter or receiver. Of course do the regular checks: often corroded battery contacts, broken or cracked boards or traces, bad solder joints.

Richard

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out?

Hey Richard, thanks for the input.

My O-scope goes down into the mV range, and I *think* should be sensitive enough for a lightweight transmitter capable of 50 feet. Unfortunately I am having trouble with it and can't get it to display *anything* right now, even with the probe plugged into the calibration socket. Was working on something quite different a few months ago, and had the settings all screwed up. Now I can only get a display with the beamfind button. Letting it percolate in the back of my head at the moment. Everything *looks* right...

There are no DIP switches on the board, merely an 8-pin DIP chip (33192C), a TO92 transistor (918), a couple of diodes and a few ceramic disc caps along with some resistors. The battery contacts are clean and the switch works, but that's all I can tell at the moment. My DMM has a freq counter built into it, and it seems to indicate a totally dead set (if I am doing it right.) Just woke up and still not thinking top notch, so giving it rest for the moment.

Genie says that a replacement only costs +/- $30.00, so may just get one of those and save this for a weekend project.

Thanks all...

Dave snipped-for-privacy@hotmail.com

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screwed

right...

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Okay, I had the intensity turned *way* down. Stupid me. I knew I wasn't awake yet.

Am now getting the O-scope to trigger when I press the button, but the transmiting frequency is so far above my scope's upper limit that it looks like a DC signal. Still, the remote is *not* dead. The guy at the support center says we might have to reprogram this remote. How would they reprogram it, without DIP switches? Any ideas? Anyone?

Thanks,

Dave

"Dave" wrote in news:chas4g$ snipped-for-privacy@library2.airnews.net:

does the door open with push button mounted in the garage? (should have one) regardless the most likely problem is it the opener unit mounted in garage. Pull off the cover, find relay, slide emery paper (both sides) through relay contacts (both normally open and normally closed ones)

In other words it is most likely dirty/corroded relay contacts in the opener unit....

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Actually, it *was* a problem in the opener. For some reason it no longer recognized the signal sent out by this remote. I reintroduced them, and the problem is now solved. The remote was working fine the whole time. Maybe it altered its signal somehow, or a power flux corrupted the memory in the opener (my guess). Either way, problem solved.

Thanks all, for your input. It is much appreciated.

Dave snipped-for-privacy@hotmail.com