# Garage Door Opener

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#### poopeater

##### New Member
HiTech said:
Look, this whole thread is getting carried away and darn silly if you ask me (2 pages of theoretical troubleshooting??). Let's top thinking about individual components going out of tune and instead locate the source of the problem logically. Copy this post of mine, take it out into your garage and get to work and don't report back here until you have some definitive results for us!

1. his vehicle transmitter's design does not provide for tweaking and poopeater states that both units operate the opener with the same results (basically disregard xmttrs. as the fault then)

2. receiver has far more components to affect proper operation so that should be suspect. First ensure that all connections terminals or wires to receiver are of good electrical integrity. Test thinngs once again to note any improvements. If not proceed to #3

3. Remove receiver module and inspect for poor solder connections, cracked foil traces, or electrically loose components. Test once again and if poor reception still exists, proceed to #4

4. swap out receiver to determine if that module is the culprit. If so, then case closed. If not proceed to #5

5. at this point if the system still isn't working properly, switch to raising and lowering the door manually!!

We need to realize that a garage door opener is an electro-mechanical device that uses a high-torque motor, mechanical linkage all interfaced to a circuit board. Mechanical vibrations over time can and have caused problems with the receiver control module. However most of the time it's been faulty xmtter packs since they get tossed about and are exposed to temperature extremes.
I think you are missing a key point to all of this. It's a pain in the ass to open up the actual motor unit of the opener. It's very simple for me to play with the tiny little transmitters.

Thus, I'd much rather try adjusting the transmitters to work with my screwed up receiver than go straight to fiddling with the large, bulky, hard to reach, overhead motor unit.

#### HiTech

##### Well-Known Member
The receiver is likely at fault when two xmttr. packs yielded the same results. I know there's the possibility of retuning the xmttrs. to a possibly detuned receiver, but what if that doesn't work? You'll have no choice to face the reality of maybe messing up things royally and having to call in a professional garage door man.

#### poopeater

##### New Member
HiTech said:
The receiver is likely at fault when two xmttr. packs yielded the same results. I know there's the possibility of retuning the xmttrs. to a possibly detuned receiver, but what if that doesn't work? You'll have no choice to face the reality of maybe messing up things royally and having to call in a professional garage door man.
How am I going to mess things up? The absolute worst case scenario would be my transmitter tuning doesn't work, and I have to go ahead and fix the receiver. I would maybe have to purchase one additional $10 transmitter to replace the one I 'broke'. That's also assuming that I break it during my attempt to tune it, which isn't likely. Why wouldn't you want to try the simple solutions first? Makes no sense. #### philba ##### New Member god, this reminds me of the old joke: Bus company hires a new driver and puts him on a route. First day he comes back with$57 in fares. The next day, he returns with $46. The third day he comes back with$290. The dispatcher is amazed - "Wow, that's the most money your route has ever made in a single day, what happened?" The driver replies "That route you gave me was a loser so I went over to 4th. Lots of people there, it's a goldmine!"

In case the point of the joke is missed, just because it's easier to muck with the transmitters doesn't mean its the right thing to do. all the evidence points to the receiver. It's staring you in the face. but, hey, do what ever you want to do.

#### Rolf

##### Member
poopeater said:
Yes, there is a metal slug inside the white tube. It's not powdered iron, and doesn't appear to be very fragile. How would I go about tuning the coil using this slug?

It is a mather of shifting it into or out of the windings, just a fraction. Make sure you can get it back were it was originaly.
We are talking about just a rew thousens of an inch. Is the slug and the tube threded? That would make it a lot easier.

#### HiTech

##### Well-Known Member
OK - I up for the game of continuing this thread going on to page 3 thanks to Rolf misleading poopeater down the yellow brick road. Now you going to need an accurate depth guage to determine where to return the coil slug to if need be. Simply counting turns of the twiddle stick doesn't cut it.

Like philba just said, the answer is very likely staring you smack in the face but you're being a "poophead" poopeater!

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#### Hero999

##### Banned
Nigel Goodwin said:
If there is a core it will be brass
Why would it be brass?

It's a conductor so it would look like a short circuit, it's more likely to be an air core.

#### poopeater

##### New Member
HiTech said:
OK - I up for the game of continuing this thread going on to page 3 thanks to Rolf misleading poopeater down the yellow brick road. Now you going to need an accurate depth guage to determine where to return the coil slug to if need be. Simply counting turns of the twiddle stick doesn't cut it.

Like philba just said, the answer is very likely staring you smack in the face but you're being a "poophead" poopeater!

philba said:
god, this reminds me of the old joke: Bus company hires a new driver and puts him on a route. First day he comes back with $57 in fares. The next day, he returns with$46. The third day he comes back with $290. The dispatcher is amazed - "Wow, that's the most money your route has ever made in a single day, what happened?" The driver replies "That route you gave me was a loser so I went over to 4th. Lots of people there, it's a goldmine!" In case the point of the joke is missed, just because it's easier to muck with the transmitters doesn't mean its the right thing to do. all the evidence points to the receiver. It's staring you in the face. but, hey, do what ever you want to do. Wow....no offense, but are you people idiots? It literally will take me 5 minutes to muck with the transmitter. If I can fix the problem (even though I KNOW that the transmitter is not the problem) in those 5 minutes, WHY WOULDN'T I TRY THAT FIRST?! Rolf said that he has doubled the range on all the transmitters he has tried by tuning them. If I can double the range, that would fix my problem...in 5 minutes, with$0 cost and very small risk.

Look at it this way. These are my two options:

1. Even though I know that the problem is with the receiver, there is a potential of fixing the issue by spending 5 minutes playing with tuning the transmitters and would cost me $0. 2. Fix the actual issue, which is the receiver. This would entail getting a ladder, opening up the garage door, removing the receiver, inspecting the receiver, probably finding nothing, having to call around to either find someone to repair it, or to find a new receiver, then install the new receiver, hope that it works with my remotes, put the cover back on, etc etc. This would take no fewer than 4-6 hours, would potentially cost me upwards of$70-$100, and also has the potential of knocking my garage door out of comission for a few days while I wait for parts/service. So yeah, my choice is between: 1. Possibly fixing the issue in 5 minutes with$0 cost and little to no risk of screwing anything up
2. Certainly fixing the in anywhere from 6 hours to 5 days, with a cost up to \$100 or more.

It doesn't take a rocket scientist to see that even if #1 only has a 15% chance of fixing my problem, I should probably try that first.

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#### poopeater

##### New Member
Rolf said:
It is a mather of shifting it into or out of the windings, just a fraction. Make sure you can get it back were it was originaly.
We are talking about just a rew thousens of an inch. Is the slug and the tube threded? That would make it a lot easier.
Thanks, Rolf. It looks like the slug accepts an allen wrench (it has a hex head cutout), so maybe it is threaded. I'm going to play with it today after work.

#### HiTech

##### Well-Known Member
tuning the xmttrs is apparently a band-aid fix IMHO. But it's your system, your time and energy so I admit. Oh, and make sure you use an iron allen wrench (hex key) if you're tuning an iron core coil.

#### poopeater

##### New Member
Philba, this whole thread reminds me of a story from when I was travelling through Africa this summer.

We were travelling through some VERY rough roads through a very rural part of Cameroon. There is no city for miles and miles in any direction, and our car stalls and will not start again. It's hotter than hell outside, and there is no way we can contact a tow truck or anyone else to help us.

Our driver gets out and figures out that the reason the car stalled is because the fuel line is clogged. So, obviously the smart thing to do is to fix the fuel line, right? Wrong. Why would you want to spend hours upon hours in the sweltering heat while the driver fixes the fuel line? You wouldn't. Hence, the driver took a can of gasoline, wedged it against the firewall in the engine bay, and ran some tubing from the gas can into the carburetor. This solution worked fine, took him 5 minutes to do, and got us moving again almost immediately.

The moral of the story is that it's not always necessary to fix the true issue if you can find a suitable work-around. Part of being an engineer is finding work-arounds to problems. Often, the work-around isn't the "best" solution, but it can be more cost effective, and if it solves the problem, then why wouldn't you at least consider it?

#### poopeater

##### New Member
HiTech said:
tuning the xmttrs is apparently a band-aid fix IMHO. But it's your system, your time and energy so I admit. Oh, and make sure you use an iron allen wrench (hex key) if you're tuning an iron core coil.
Why would it be bad to use a non-iron wrench in an iron core coil?

edit: read my post, above. Part of being an engineer is finding suitable work-arounds to problems. You don't always have to fix the actual problem, per se. It's not always the best option.

#### philba

##### New Member
poopeater said:
Philba, this whole thread reminds me of a story from when I was travelling through Africa this summer.

We were travelling through some VERY rough roads through a very rural part of Cameroon. There is no city for miles and miles in any direction, and our car stalls and will not start again. It's hotter than hell outside, and there is no way we can contact a tow truck or anyone else to help us.

Our driver gets out and figures out that the reason the car stalled is because the fuel line is clogged. So, obviously the smart thing to do is to fix the fuel line, right? Wrong. Why would you want to spend hours upon hours in the sweltering heat while the driver fixes the fuel line? You wouldn't. Hence, the driver took a can of gasoline, wedged it against the firewall in the engine bay, and ran some tubing from the gas can into the carburetor. This solution worked fine, took him 5 minutes to do, and got us moving again almost immediately.

The moral of the story is that it's not always necessary to fix the true issue if you can find a suitable work-around. Part of being an engineer is finding work-arounds to problems. Often, the work-around isn't the "best" solution, but it can be more cost effective, and if it solves the problem, then why wouldn't you at least consider it?

do what you want to do. it just amazes me how people will waste their time fiddling the obviously wrong knobs... and there is a difference between a band-aid and a fix.

#### poopeater

##### New Member
philba said:
do what you want to do. it just amazes me how people will waste their time fiddling the obviously wrong knobs... and there is a difference between a band-aid and a fix.
If after tuning the transmitter, my garage door opener works from at least 10 feet away, then it's not a bandaid. It's a fix. Like I said before, I'd rather 'waste' 5min of time if it has the potential of fixing my issue than to waste 6 hours fixing it for sure.

#### Rolf

##### Member
Wrong!

Hero999 said:
Why would it be brass?

It's a conductor so it would look like a short circuit, it's more likely to be an air core.

It has nothing to do with being a conductor. Coils inductance is determined (and affected) by the material they are wound on, it being air, or powdered iron. I have newer seen brass used, but it is used for trouble shooting since it lowers the inductance.
So your logic is faulty. Iron is a conductor also but is raises the inductance!

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#### Hero999

##### Banned
No my logic isn't faulty, yours is.

Iron cores aren't conductive, they're normally made of ferrite which is an insulator.

A brass core in a coil would behave like a short circuit turn in a transformer because the primary would induce eddy currents in the core leading to a very high eddy loss.

#### HiTech

##### Well-Known Member
poopeater said:
Why would it be bad to use a non-iron wrench in an iron core coil?
I was steering you down that yellow brick road.

#### Nigel Goodwin

##### Super Moderator
Hero999 said:
Why would it be brass?

It's a conductor so it would look like a short circuit, it's more likely to be an air core.

Brass cores have always been used, ferrite cores increase the inductance (but are only suitable for low frequencies), brass cores decrease the inductance, and are suitable for much higher freqencies. So an adjustable core at VHF is likely to be brass.

For the older ones amongst you, brass tuning cores were commonly used to tune TV sets back in the VERY old mechanically tuned days.

Quick update, a quote from page 23.2 of the 1976 5th edition of the RSGB Handbook (part 2):

For coils wound on Aladdin type F804 formers, and having a winding length of 0.3 - 0.8in a dust-iron core will increase the inductance to about twice the aircore value: a brass core will reduce the inductance to a minimum of about 0.8 times the air-core value.

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#### Hero999

##### Banned
Why aren't eddy currents a problem then?

#### Nigel Goodwin

##### Super Moderator
Hero999 said:
Why aren't eddy currents a problem then?

No idea?, perhaps because it's brass and not iron? - perhaps someone with a much more recent theoretical background might be able to help?.

Any way, Eddy Currents isn't a problem at the moment, the Police have him locked up

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