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Topic # 115206 18-Mar-2013 06:24
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To cut a long story short, occasionally the garage door motor unit (Garador) does not respond to the remotes.  The wired switch always works, and it's not the
remotes as there's more than one.  When it's working an LED flashes on the unit to indicate a signal's been received, there is no flashing when not working.

I originally thought that the movement of the unit was causing a loose connection as I could fix it by jiggling the wired connections, but have come to realise that I can fix it just as well by lightly touching the co-ax socket on the back of the motor unit (presumably the socket is for an extended aerial lead).

I'm presuming that there's some static buildup that's knocking out the circuit board and I'm discharging it by touching the co-ax.

Has anyone had similar problems?  Am I nuts to run a cable from the co-ax to something in the garage that will earth it?

Thanks

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  Reply # 783213 18-Mar-2013 07:29
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Silly question: you've changed the remote batteries, right?




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  Reply # 783224 18-Mar-2013 08:20
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What brand? We've had a similar issue where the receiver appeared to have lost the remote settings and oddly enough grabbing onto the antenna somehow made it work (would be strange for two sets of batteries to be flat at exactly the same time). I can't remember how i got it working again, I just recall re-training one of the remotes a few times and mashing random buttons at the same time. I even RTFM which didn't help at all.

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  Reply # 783257 18-Mar-2013 09:20
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What sort of remote?
Where is the aerial on the unit...is it fully extended?

We have issues with the garador unit but not the merlin !
Depends on the batterys in the remote... and the direction you point or hold the remote.
Gets worse when there the garage is 'chokka'.

I'd look into using that extention aerial socket.
Anyway... I like having the remote only work infront of the door as opposed to 'down the road'...makes me feel more at ease incase of accidental 'push'.


edit: oh forget to mention...  A few years back one of our remotes suffered from moisture (hot car then cold car)... this shorted out the board and made the door open and close itself. The remote also didnt want to work in cold conditions. 



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  Reply # 783270 18-Mar-2013 09:31
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My Merlin has a big piece of wire connected as an antenna.




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  Reply # 783572 18-Mar-2013 18:40
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It's definitely not a problem with the remotes (which are different brands to each other), it's a problem on the motor unit itself which (only occasionally) ignores the RF signals the remotes send. 

When it happens I can fix it by just touching the motor unit...that's why I'm thinking it's static electricity.

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  Reply # 783583 18-Mar-2013 19:04
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Are you discharging static or acting as a better aerial?



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  Reply # 783618 18-Mar-2013 20:10
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Definitely discharging as it's a two-stage process:  touch'n'discharge followed by press remote (and curse).

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  Reply # 783643 18-Mar-2013 21:19
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Static electricity has no significant effect on the remote control. EMC/EMI compliance testing is done with a few thousand Volt contact discharge to connectors.

Looking at the accessories they sell, the connector is more likely for infra-red safety beams.

If you have the newer "tri code" model, then it uses code hopping which changes the transmitted code to a pseudo random code based on the last code. The receiver needs to track the last codes in order to know what the next code is. Because the button can accidentally be pressed when out of range, it actually accepts a block of codes. However, if the button is pressed many times while out of range then you loose synchronization. In this case you need to press the button a few times and it will re-sync.

How old is it? Electronics age and if it drifts too far off frequency then it is like a badly tuned radio and will not respond as it should (and affected by temperature, and proximity to your body). I have one remote like that, I have to hold it by it's ends between fingers and not in my hand (just too lazy to get a replacement).




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  Reply # 783654 18-Mar-2013 21:52
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The system is about six years old.

There are two separate remotes, one in the car, the other is a keypad fixed to an external wall (yes it's wireless, yes it's got a battery and no the batttery doesn't need replacing). When the problem occurs neither remote works.

To fix it I "touch" the motor unit, not the remotes.  Then using either remote will get the door moving,  without changing batteries, without pointing to Mecca, without trying a few times - I touch the unit and it will open on the first press of either remote.



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  Reply # 783742 19-Mar-2013 07:25
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I don't know about the garage door, but my Mum has a dodgy hip, if I bring her over will you lay hands on her to see if you can help her too? ;)




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  Reply # 783758 19-Mar-2013 08:51
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Call a garage door tech.
From all the replys here, we seem to think its a temperature or frequency shift issue.
Have you got a freezer or another motorised device in the garage? Could it be sending out some random spike?

Do you know what freq the garage door works within?


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  Reply # 784681 20-Mar-2013 19:32
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Gooseybhai: Do you know what freq the garage door works within?

Web site suggests 434MHz (looking through manuals).




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  Reply # 784695 20-Mar-2013 20:09
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The frequency is good old-fashioned 433Mhz. There are indeed other things on that frequency locally, notably a burglar alarm, but no fridge or anything else electric in the garage and I don't think the wheelbarrow is broadcasting. 

I can understand the frequency drift due to aging components, but can't see how just touching the motor unit fixes its ability to receive signals.  The same goes for the alarm sending out a signal and interfering, I can see it would happen but why does touching it fix it?

There have been times I have driven home and opened the door with the remote but one minute later it won't respond when I try to close (with the remote), until the healing hand touches it.  Hence my theory that the motor operating, or the chain moving, is causing a static buildup.

Or do we think a current spike could cause the problem?


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  Reply # 784818 21-Mar-2013 09:52
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could it be a loose solder joint on the antenna to the board of the opener? or somthing similar in the unit?

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  Reply # 785223 21-Mar-2013 22:14
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This is a possible explanation for what can cause such a sensitive electrical connection that would one minute work and the next not. Many manufacturers still do not understand how lead free and leaded solder is incompatible. The two solders solidify at different temperatures, and when they solidify they shrink. So at a microscopic level the lead free solder solidifies and shrinks first, then the leaded solder solidifies and shrinks. Micro-fractures develop and the joint is fragile. Over time the solder dries out and the solder becomes brittle (in addition to being fragile). Six years sounds about the right ballpark for having issues. In the mid 90's there were related issues with car fuel pump relays and a common "solution" was to whack the dashboard in a certain place where the relay is mounted. I have fixed a few of those relays and it is surprising what happens to the solder joints. Last year we found a similar issue on our fancy expensive fridge which prevented the water dispenser from working. Unfortunately few service people know about this, typically it is just a matter of replacing a whole module (same with our fridge, which was under warranty, but I showed the guy where the issue was so he can fix it).

I am sceptical that a service centre will fix solder joints, but see if you can find someone (neighbour?) that is good with soldering electronics and ask if they would just resolder the RF module to the main board in case a solder joint is cracked.




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