So with new batteries installed (note to come about this later) my garage door opener did not work as it should.
When I cracked it open i quickly realized the problem... It was one of my arch nemesis-es.. a tactile switch.
I'm not sure if these things are prone to failure or if it just me. Long story short is that i have several devices that have had a failing tactile switch in it.
So join me wont you please as i embark upon an adventure in changing a switch in my Liftmaster Garage Door Opener.
Disclaimer: likely bad advice to follow, exercise critical thought if you think you wish to embark upon a similar adventure.
Tools you will need:
Pliers (preferably needle nose)
Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.
Step 1: Opening Your Liftmaster Garage Door Opener
Step one is fairly simple it just involves cracking the thing open.
Locate the notched area on the side of the casing which allows a a screwdriver like device to be place.
A note of caution. You can really bugger up your casing if you just start tearing and prying so use a gingerly touch, and know that likely you will burr up the casing in doing this.
The case is simply snapped together so in my experience in unsnapping cases the frequently break the snaps so just be cautious.
Step 2: Pull Out the Offending Circuit Board
This is quite simple as the PCB is just sitting nestled in the case. The up shot of this is that if you have just struggled to open the case likely the case will break free and simultaneously you will drop the device and the board will fall out.
Step 3: Remove Old Switch
Ok this is where things get a little funky on my end. To do this properly you should get a Desoldering iron. A desoldering Iron greatly improves you ability to complete this project with out destroying your circuit board. What a desoldering iron does is allows you to remove the molten solder. You need this as there are 4 contact points for this switch so you cant simply unsolder one leg of it.
I had stole my fathers desoldering iron but he got wise to my shenanigans and took it back. I had not realized this had transpired until i was knee deep into this project.
My un-recommended work around is to destroy the switch. This adds stresses to your circuit board and could cause a crack in the board which would destroy it. Also any time you are actively putting destructive forces into such a small device its hard to make sure you are only breaking the parts you need.
(un-recommended work around cont.) Once you remove the physical portions of the switch which were not connected to the board you need to remove the leads which are still soldered into the board. to do this I attach a vise grip wrench to the remnants and headed the solder. Then gravity will assist in removing the leads.
(un-recommended work around cont.) Next you will notice that there is solder left blocking the holes. This is usually easily cleaned with a desoldering iron. So as you can see this is a really useful tool for this project. As this is not an option for me i simply heat up the solder and the blow a burst of air from my mouth. This is another tricky task as its hard to time the action right and you run the risk of burning your self in addition to you cannot control there the blown solder will go. just be sure (if you are trying this un-recommended method) that you blow the solder away from the board. you don't want slag creating short circuits on other parts of the board.
Once you have successfully removed everything you can move to the next step. It should be noted that you don't always have to remove the excess solder, i just find it makes it a lot easier when placing the new switch.
Step 4: The Switch!
Low and behold radio shack still sells parts and pieces. The are in the back behind all the dust covered stuff. you could probably find these pieces online as well.
To add more excitement to this story i got he wrong switches. I accidentally purchased surface mount switches.
This board is obviously a through hole style board. So make sure you purchase a switch that is correct to your board type. if your board is like mine you need a through hole type switch.
so we get to do another un-recommended work around.
This un-recommended work around is to simply bend the connection points down and convert it to a through hole connection type switch. This #1 issue with this is that it weakens the switch before its even part of you board. another problem is that the leads are not long enough to go through the board so you cannot be 100% certain that you have made a good solder.
Step 5: Soldering the Switch to the Board
When soldering the switch (and most things in general) I find it very useful to prep the thing i'm about to solder by applying a little solder to each part first. So First i add the solder to the four contact of the switch.
Next i put the switch in place on the board and hold it there with some tape.
Then I solder all the pin in place on the board.(This is much easier with the through hole switches) If you notice i also prep my soldering iron with just a little bit of solder as well so that i can get enough solder on the board.
Once you have soldered everything in place its wise to test you solder by lightly grabbing the switch and see if there is any free movement on the switch. Try to move it back and forth and side to side. If it feel like it wiggles even in the least bit, go check your solder joints.
(un-recommended work around) Since i have really short leads in order to make sure I've got a good solder connection i follow up and head the front side of the switch to make sure the colder that is connect on the back is also connected on the front. This is not recommend as it can burn the board and switches so do your self a favor and get the right materials.
Step 6: Reconstruct and Go About Your Day!
After you have checked you soldering job al that is left is to put the battery back in and reassemble the case.
Step 7: But Here Is the Twist in My Story...
So once i had it all back together it still didn't work. Then i realized that i had done the switch-endectomy on the wrong device. We have two garage door openers and one needed a battery replaced and the other needed the switched replaced. So naturally my luck would have it that I replaced the battery on the one that had a bad switch and and switched the switch on the one that needed a battery... life is full of surprises. So i got to to another switch-endectomy and replaced that battery and all devices are good now even if one of them got a little unneeded surgery.
So before you change the switch in the wrong device make sure you grabbed the right one, or simply check to make sure your battery is not dead.