Simple button Repair (I hope)

[kr3pt]

Hey guys, Noob here.
We had a monitor at our office that had a problem where it would randomly start cycling through all of its inputs. I figured it was just that the button was stuck. My boss decided to give it a good whack from the side. This turned out to be a not so good idea because after he did that it would no longer turn on at all!
He looked into it and we were 3 days out of the return period with no warranty, so he told me to trash it.

Instead I took it home and took it apart. What I found is that the power button is a tiny momentary button that uses a tiny convex metal cap. when he hit it, that cap came off. The rest are intact and seem to have some orangish glue holding them in place.
To confirm my theory i took the look "cap" and put it over the area that it should be in and depressed it. This worked and the power came on.

What would be my best route to take to fix this at least to a usable state? If i should glue it like the others, what glue should I use? all insight is welcome.

 

[(*steve*)]

That's a small tactile switch.

Everything will be OK unless you put it down on synthetic carpet...

Just kidding, kinda. There's probably nothing on that board which could be easily damaged by static. The same is not true of the rest of the monitor.

Depending on how the buttons are mounted for this switch, you may have room to mount a larger tactile switch and have the actuator protrude through the casing, or you may have to locate one of these very thin switches.

I'll see if I can locate where you can get one of them...

This is a surface mount, snap dome, tactile switch. Better hurry, they only have a million in stock. (Check it carefully to make sure it is the same size before ordering).

The next question is, can you do surface mount soldering? (and I suspect that the answer is no).

I recommend you get that part, and find a local person (maybe through a hackerspace or makerspace, or an amateur radio club) to replace it. The fix should be as simple as replacing this 20c part. I'd be happy to come over and fix it if you pay the airfare :-D

 

[(*steve*)]

Actually, if you're really lucky, you might be able to tape it (the dome) in place. If you have some kapton tape, this would be ideal (use a very thin strip)

 

[kr3pt]

Thank you for the good information, humor, and fast response.. Unfortunately You are corredt. I'm not very good with soldering. I do it occasionally on a basic level (LED's n such). Is the Kapton tape you're refering to the same stuff used with 3D printers? I could justify picking some up for that.
If that doesn't work, I'll look for someone local.
Pittsburgh, pa if anyone is interested

 

[(*steve*)]

You could try any thin adhesive tape (I'd give duct tape a miss though). It may work temporarily. Kapton tape (yep, the same stuff as used on 3D printers) would be ideal.

You probably want a piece 5mm wide and 20mm long -- not much at all! (And stick it to the board, not the black insulating covering).

 

[kr3pt]

Gotcha.
Guess its hard to tell by the image but the dome is about 3.5mm and the plastic insulation/housing is about 4.75mm

 

[kellys_eye]

You should be able to trace the pcb tracks back to the actual connector that takes the on/off signal off-board to where ever it goes and solder wires there instead.

Fit a small toggle switch somewhere on the back panel. I doubt if aesthetics are an issue????

 

[kr3pt]

Sorry that I disappeared for a couple days.
Aesthetics are not an issue, and if its possible for me to solder a new switch at the connector I may want to go that route. I did order some Kapton tape but I'm at the mercy of the postal service now!

 

[kellys_eye]

Inside the actual switch body I see the central and edge contacts..... they look to be pretty poor - could just be the cr@ppy focus though - so even if you could kapton-tape the dome over it you may still be looking at shonky/none operation.

It looks as if the pushbuttons are used with series resistors to form an 'analogue' voltage switch so they aren't multiplexed therefore won't have individual connections at the on/off board connector. As a result you would have to wire directly to the solder pads at the relevant switch if you wanted to fit (say) a toggle (it would have to be a momentary, spring-biased action) or momentary push button elsewhere on the panel.

 

[kr3pt]

Sorry about the focus. Macro photos aren't my forte`
I received my kapton tape and put some on and it looked pretty good, but it was a tiny bit off center. It worked when I depressed the button, but unfortunately stayed depressed! I took a second crack at it and got it centered much better and the button itself is working great! I have not yet re-assembled the monitor which may tell a different story, but I'm happy its working. While I was tinkering I did jump the #3 and #4 solder points and this also works. So If the kapton tape doesn't hold up, I will take a crack at soldering a new momentary switch at that location. I do already have a small momentary button around the same size from an arduino prototyping kit I bought a while back.

Thanks for the help! I will update if there is any news.

 

[kr3pt]

Re-assembled the monitor. The power button does turn the monitor on and I can visably see the backlight, but all I get is a black screen which is odd because I know this monitor (and most) will boot up and show the brand logo etc.
Maybe the wrong place to ask, but could it be from anything I did? Maybe static related or possibly the ribbon cable was put back in twisted or backwards?

 

[kellys_eye]

that had a problem where it would randomly start cycling through all of its inputs.

Still stuck on the wrong input perhaps?

My boss decided to give it a good whack from the side. This turned out to be a not so good idea because after he did that it would no longer turn on at all!

It's your bosses fault then - have some stern words with him......

 

[kr3pt]

Still stuck on the wrong input perhaps?

It's your bosses fault then - have some stern words with him......