Can you help me fix this mirror's tactile/proximity button?

Thread Starter

rambomhtri

Joined Nov 9, 2015
551
Original title: How in heavens a mirror defogger is connected? (Solved! By 2 hair like cables that are the heat element, soldered to the main cables)
Hello, my uncle has this fancy mirror with ambient LED, digital clock, mirror defogger...

Apparently, half of the LED stopped working (FIXED!), so did the tactile buttons and the defogger (FIXED!). He "tried" to fix it but I think he really messed it up...

First I am testing the basics... The main cables are connected to a 230V AC outlet, and these go to an LED driver, another driver or transformer and to the mirror defogger (this one has a relay, to get turned on or off).

Disconnected everything except those 3 elements, and the driver and transformer both output 12.36V DC, so I guess they work. I have to fix the buttons first, he unglued them and everything is "flying around"... But the thing is...

The mirror defogger has a really weird type of connection, the input cables are not connected to anything apparently, they go inside a glob of silicone, and that's it.

I found the mirror as it is in the pictures, and I believe my uncle did a really bad job, probably broke something...

LMC20230727_185322_lmc_8.4.jpg

LMC20230727_185336_lmc_8.4.jpg


MY first question is... how is the defogger powered? (FIXED! My uncle pulled the cable and ripped the tiny cables that heat the defogger. I have fixed all of this, soldering the hair-like heating cables to the main cables again, all working)
I see no connection or cable or copper or soldering pad under the silicone patch. Unless my uncle ripped apart something that was there before, I don't understand. At first I thought it really was some kind of sensor, a thermocouple to make sure the heater's temperature was controlled and monitored. But no, those cables are actually the INPUT of the heater element.

Also, I've noticed this LED broken path... Is it normal? Should I solder it? (FIXED! Yes, I soldered it and now the full strip works)
Why are there scissors there? (FIXED! To let us know we can cut that part and end the strip there)

LMC20230727_185608_lmc_8.4.jpg

Here are the pictures of the tactile button:

1691256544237.png

1691256555444.png

1691256567220.png

1691256580781.png

1691256594769.png

Okay, the mirror has 2 tactile/proximity buttons, one for the defogger, the other for the LED strip. The mirror has an input cable of 230V AC, this cable goes to 3 devices: an LED driver (12V DC) for the LED button and LED strip, a transformer (12V DC) for the defogger button and the defogger itself (input 230V AC).

The defogger works fine, the defogger button is OFF by default, and when you put your finger next to it, it turns RED and turns on the defogger with a relay that's in the 230V AC cable. I see an increment of 30W, all fantastic. You put your finger again next to the button, goes back to white and turns off the defogger.

It's the LED button the one that does not work. By default it's ON, so when you plug the mirror to the outlet, the LED strip turns on, however, you are not able to turn the strip off, because the button doesn't do anything. Also, I think the switch for the LED strip must be in the button's board, may be a transistor acting as a switch that's not working, because I see no relay for the strip.

Here's a video of the behavior, and also a little test I made to check if one component of the board was heating up much, which pretty much looks like it's T1. I am pouring drops of isopropyl alcohol, not water in case anybody thinks that:

1691257433308.png

These videos can be played (streamed), it's not necessary to download them:

https://mega.nz/file/EcAS3a5Q#7v34U76VgEWjScBZ_A4FVYW_rmoquGd6NFdTmgw8T4o

https://mega.nz/file/pN5jgLQa#FO1pSK_LZdDPm8OEIUrpQ4JrRym45G7QDZAUmWQU71Q

One thing I don't like is that it does not look like I can buy this whole thing... so I either fix it or will have no way to turn the the LEDs off.

Here's the an abstract draw of the circuit (by transformer I mean the LED Driver, which has a transformer of course):

May be the LED strip is not exactly like that, I don't know, but I think it is. The first thing that I don't really understand is the 4 cables in the LED strip.
Shouldn't 2 cables just be enough?
Why those 2 extra cables at the end if all are parallel?
May be so if you break the strip once in the middle, it keeps working as it would flow from the other side?
1691292047360.png
The circuit for the defogger is the same, except it comes from the transformer and not the LED driver (also a transformer), and you replace the LED strip by a relay that acts a s switch for the defogger, which breaks the 230V AC cable of the defogger. This part works fine.
 
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WBahn

Joined Mar 31, 2012
29,831
I have seen that pic and many others... my question is HOW is the cable connected to the heater element? Makes no sense if you look at my pictures... the cables are submerged in silicone and that's it, apparently.
The pad has thin wires in it that snake back and forth across the surface of the pad to transfer heat to the back of the mirror. The electrical wires are connected under that badly shattered cover. You would probably need to scrape things away carefully to expose more wire because the initial part of the wire was likely ripped out of the pad.
 

Thread Starter

rambomhtri

Joined Nov 9, 2015
551
The pad has thin wires in it that snake back and forth across the surface of the pad to transfer heat to the back of the mirror. The electrical wires are connected under that badly shattered cover. You would probably need to scrape things away carefully to expose more wire because the initial part of the wire was likely ripped out of the pad.
I haven't seen any cable soldered to the blue or brown one, neither any cable coming out from the white surface (I was expecting this but I haven't seen any, that's why I am shocked). Unless my uncle completely ripped off the cables... but they are not expected to be hair thin cables, right?

As you can see I have scraped a bit the surface and haven't found any trace of cables... are these supposed to be hair thin??? I can clearly see the S shape of the heater... a thin like cable wouldn't make the shape obvious at all. May be my uncle ripped the cable and even took some of it away from the insides, that might be the reason I see nothing but white plastic, and the input cables flying there, without nothing to solder to.
 
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ElectricSpidey

Joined Dec 2, 2017
2,756
My guess would be that the elements are not very thin wires but in fact wide strips of a conductive type of material where the exposed areas under the patch easily blend in with the rest of the back.

Try doing a resistance check where the power cables used to connect.

In that picture you can see the indents of the elements, figuring the scale I would say 1/2 to 3/4 inch wide.
 

Thread Starter

rambomhtri

Joined Nov 9, 2015
551
I am gonna show you a picture of the area, closer... I literally see no cable or traces of it going into the white pad... unless the heater element is... this?

LMC20230728_115919_lmc_8.4.jpg

How is the heater element the thickness of hair???
Is that supposed to stand 30W??? (rated defogger)

Now the question is too... which of those cables are the hot and neutral?
Or it doesn't matter?

They are connected directly to 230V, AC, and are rated 30W. I am reading a resistance of 1788 Ohm between those cables.
Actually looks fine since
P = i^2 x R
30 = i^2 x 1788
i = 0.1304 A
P = u x i
30 = u x 0.1304

u = about 230V, all seems to work
 
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wayneh

Joined Sep 9, 2010
17,493
... unless the heater element is... this?
Yup, that's it.

Is that supposed to stand 30W??? (rated defogger)
Sure! Don't forget the length. It's probably a fractional watt per inch. And it's surrounded by material that conducts away heat.

Now the question is too... which of those cables are the hot and neutral?
Or it doesn't matter?
Nope, it's very much like an incandescent lightbulb.

They are connected directly to 230V, AC, and are rated 30W. I am reading a resistance of 1788 Ohm between those cables.s
Actually looks fine since
P = i^2 x R
30 = i^2 x 1788
i = 0.1304 A
P = u x i
30 = u x 0.1304

u = about 230V, all seems to work
:)
 

WBahn

Joined Mar 31, 2012
29,831
I am gonna show you a picture of the area, closer... I literally see no cable or traces of it going into the white pad... unless the heater element is... this?

View attachment 299285

How is the heater element the thickness of hair???
Is that supposed to stand 30W??? (rated defogger)

Now the question is too... which of those cables are the hot and neutral?
Or it doesn't matter?

They are connected directly to 230V, AC, and are rated 30W. I am reading a resistance of 1788 Ohm between those cables.
Actually looks fine since
P = i^2 x R
30 = i^2 x 1788
i = 0.1304 A
P = u x i
30 = u x 0.1304

u = about 230V, all seems to work
You found them!

I'm actually a bit surprised by the resistance matching up so closely with the power calculations, because heating filaments generally have a very strong temperature dependence to the resistance. But, in this case, it's probably not too surprising because the temperature of the mirror isn't supposed to go up by that much, so the operating and room temperature resistances are pretty close.
 

Thread Starter

rambomhtri

Joined Nov 9, 2015
551
Okay, I will solder the cables, that should get the defogger going if the relay and tactile button works.

Now, about the LED strip... This should be soldered, right?

Screenshot_20230728-204028_Chrome Beta~2.png

I don't even know how that happened... Why are there scissors there anyway?
May be to know you can start removing each chunk of those to make the strip shorter?
 

bertus

Joined Apr 5, 2008
22,264
Hello,

The scissors are the points here the sections start and end.
You can not cut on other places as the section would not be complete.
You can cut the ledstrip at the scissors to match the length of your project.

Bertus
 

Thread Starter

rambomhtri

Joined Nov 9, 2015
551
Hello,

The scissors are the points here the sections start and end.
You can not cut on other places as the section would not be complete.
You can cut the ledstrip at the scissors to match the length of your project.

Bertus
Thanks! So I should solder the broken strip, right?
 

wayneh

Joined Sep 9, 2010
17,493
I think the bottom line answer is that we can't tell if there should be a continuous connection at that spot. My hunch says yes, because the gap is too small to avoid an errant connection otherwise, But it's really just a hunch.
 

Thread Starter

rambomhtri

Joined Nov 9, 2015
551
I think the bottom line answer is that we can't tell if there should be a continuous connection at that spot. My hunch says yes, because the gap is too small to avoid an errant connection otherwise, But it's really just a hunch.
I am sorry... you are right. Here's a pic:

1690632531624.png

Mirror from the back, LED strip connected to a 12VAC driver. There would be no sense in that broken spot, right?

Also... apparently my uncle said one day suddenly part of the LED turned off. If you break that strip in that spot, there should be absolutely no portion turned on, right?

All the entire strip should fail to work is my guess.
 

MisterBill2

Joined Jan 23, 2018
17,742
If there is a break in the conductive strip, possibly a patch with a short piece of wire held tightly against the strip while it is glued i place may work. OR a small amount of printed circui repair paint may work to repair the gap..
 

wayneh

Joined Sep 9, 2010
17,493
If you can't close the gap easily, use your ohmmeter to find other places on the strips that are in continuity with the broken connection. Scraping off a little paint or whatever may expose a copper pad. You want to find spots that are much easier to solder a bridge wire to. These things can be a little tricky to work on.
 

Thread Starter

rambomhtri

Joined Nov 9, 2015
551
OOOOOh, wait... the strip has all the LEDs in parallel, so that's why even with the strip completely separated in the middle, my uncle was able to turn on part of it.

I have assembled everything and finally the whole strip turns on, also the defogger works perfectly now.

However, there's just one thing more broken: one of the buttons, the one that turns ON/OFF the LEDs. After plugging the mirror to 230VAC, the LEDs turn on, but the button that turns them off doesn't do anything, it's tactile.

Let me explain real quick the mirror:

It has 2 tactile buttons, one turns ON/OFF the defogger, the other one turns ON/OFF the LED strip.

After assembling everything back, all works except the LED button. The little area of the button is notably warmer than the defogger button. My guess is, the tactile button is broken, some component is broken and is heating up a lot. However, the power makes sense: when the mirror is connected to the outlet, there are 30W from the LED strip, and the defogger increments that to 58W (the 30W I told you about before). So power wise, everything looks fine.

While I check the button board... the strip has 2 cables with 12VDC in one side, and 2 other cables in the other end. I don't understand how in total 4 cables are attached to the strip... should not just be 2 cables?
 

Thread Starter

rambomhtri

Joined Nov 9, 2015
551
Here are the pictures of the tactile button:

1690823911151.png

1690823959067.png

1690823974425.png

1690823988208.png

1690824004340.png

Since the defogger works fine, so do the LEDs, and this board is the only thing between the driver/transformer and the LED strip... something wrong must be going on here... nothing looks burnt though.

One thing I don't like is that it does not look like I can buy this whole thing... so I either fix it or will have no way to turn the the LEDs off.
 
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