How to repair the LCD display of a digital watch

[Jose Capco]

Dear NG,

I have a not so expensive digital watch that is not water resistant. I
think that water went into the watch after I washed my hands and then
some of the digits will not show correctly.

I know that these digital watches have an LCD and there is a conducting
"rubber" (What do they call this rubber?) that connects the LCD to the
PCB of the watch (Can someone explain the science behind this?), I hope
that you know what I mean! The rubber is attached to the LCD by some
kind of adhesive... and when water goes there I suppose the adhesive
will become ineffective and so some of the display in the LCD will not
show up. (Like 8 becomes 9 in the LCD display)... If I push the LCD a
little so that the rubber allows current in the LCD, the display becomes
OK...

Can anybody give me some suggestion or comments on how to repair this
thing ... Thank you very much.

Sincerely,
Jose Capco

Sent via Deja.com http://www.deja.com/
Before you buy.

[craig osborn]

Jose try cleaning all contacts gently with cotton swab or ball. I use
denatured alcohol, be carefull and leave no residue. IF the etched glass is
not damaged it should work. DO not touch contact areas after cleaning. The
conductive pad is NOT attached to anything they stick after time to the
glass, makes it look like it's glued, it's not.
JEFF

Jose Capco <jca...@my-deja.com> wrote in message
news:8opim2$vtu$1...@nnrp1.deja.com...

[kb3]

I don't like to be a wet blanket, but I have tried several times to clear up
misbehaving LCD's in a variety of devices and have never once succeeded.
Time for a new watch. I recommend the Timex Data Link...set it with your
computer. $35 or so at Walmart.

"craig osborn" <ee...@worldnet.att.net> wrote in message
news:yVZr5.4618$U41.3...@bgtnsc05-news.ops.worldnet.att.net...

[Weijenberg]

I tend to agree with craig: it can be done.

Additional to his cleaning advice: it's critical to 'clamp' the sandwich of
PC-board, rubber and LCD in aright way.
Don't overstress the compression, just tight is OK, too tight deforms the
sandwich and locally contact may get lost.

About the physics behind the strip:
If you watch closely, you'll notice that the strip consists of a large
number of conductive and isolating rubber strips, each some tenths of a mm
thick.Clamping this sandwich between the PC board and the (translucent)
conductive strips on the LCD makes each PC-board terminal to connect to the
LCD terminal, without the need for adjustment of the connector in between.
The contact fails if the rubber is damaged, the contact is dirty, or the
claming pressure is uneven.

Success with your repair, you'll save $35 or so at Walmart.

Dick Weijenberg

kb3 heeft geschreven in bericht ...

[WEBPA]

>Dear NG,
>
>Thanks a lot for all your response both by email and newsgroup. I
>followed your advise and in addition I tightened the screw and I was
>successful. Thanks too for giving me some scientific explanation of the
>conductive rubber in digital watches. .. I do have another question
>though (that is out of curiousity), I have seen so many cracked LCD from
>digital calculators and watches and I do notice some kind of black inky
>fluid stuck in the display when they crack .. what are they? and why are
>they there? It seems that my question really is .. how do these LCD
>work? ... These watches and calculators are not repairable I persume,
>unless one buys the LCD specific for them, but do manufacturers sell
>only the LCD of a specific digital device?
>
>thanks again,
>
>Sincerely,
>Jose Capco
>
>
LCD means Liquid Crystal Display. The "black inky fluid" is the liquid crystal
material. Which is a chemical with the property that it changes the
polarization of light passing through it when an electric field is applied. The
change is analyzed (made visible) because of the polarizing filter in front of
the display.

Avoid getting chemicals like this on you skin..they absorb directly through.

Paul Weber
Albuquerque, NM
we...@aol.com
webpa

[Sydney, Australia]

You can try to clean the "rubber" conductor and the integrated circuit
with surgical alcohol or clean metillated spirit, usuallly help.

Thomas
www.watchrepair.com.au

"Jose Capco" <jca...@my-deja.com> wrote in message
news:8opim2$vtu$1...@nnrp1.deja.com...

[Andre]

In article <sr0sdg...@corp.supernews.com>,

"kb3" <k...@mypad.comDELETE> wrote:
> I don't like to be a wet blanket, but I have tried several times to
clear up
> misbehaving LCD's in a variety of devices and have never once
succeeded.

I have. The secret is to clean both the LCD contacts,AND those on the
watch board with isopropyl alcohol. This works in 99.7% of cases.

The trick is to make sure you put the display the right way round .. !

:-)

CAREFUL though, use minimal pressure on the LCD as the metal contacts
are fairly delicate and are easily damaged.

--
Andre de Guerin
Email <da...@yahoo.com>
Who is "General Failure" and why is he reading my disk drive ?

[sports...@gmail.com]

I have an old timex marathon watch. Model number 745 e or f 8. It has water damage to the LCD screen. Will isopropyl alcohol or anything else help get this black streak mark out on the LCD screen? Will cleaning up the rust in the LCD screen help as well or is it just to late? Timex will not replace this LCD screen as this watch is so old it has been discontinued. I would post a picture of the damaged watch with the bad LCD screen but I don't know how. I can also say this, when taking into a watch repair place, they took the LCD screen apart and it when putting it back together the little black streak mark across the watch went from little to big! They made the situation worse! Please help me with this as to anyone having suggestions. My name is Robert! Thanks!

[sports...@gmail.com]

Also, will trying isopropyl alcohol on the LCD screen help if there is already this black line in my old timex marathon watch or is it just to late. If your only suggestion is to call timex and ask them for A replacement for this LCD screen that option won't work as they dont make this watch anymore or service parts for this watch anymore. So any help as to if this watch LCD screen can be repaired would be greatly appreciated. Thanks and hope to be here from you all soon. Robert.

[N_Cook]

On 21/06/2018 13:31, sports...@gmail.com wrote:
> Also, will trying isopropyl alcohol on the LCD screen help if there is already this black line in my old timex marathon watch or is it just to late. If your only suggestion is to call timex and ask them for A replacement for this LCD screen that option won't work as they dont make this watch anymore or service parts for this watch anymore. So any help as to if this watch LCD screen can be repaired would be greatly appreciated. Thanks and hope to be here from you all soon. Robert.
>

My guess is black streak was a hairline crack of the glass , from a
knock. Close handling then enlarged the crack.
Look for a "spare or repair" scrapper on Flea-bay or wherevever, with a
different fault of course

[Terry Schwartz]

Most of the Timex Marathon watches are very inexpensive -- any repair would quickly eclipse the price of a new watch. Even if Timex could supply a replacement, it would not make sense to go down that route.

[Ron D.]

For info on the elestometric connector look for "zebra strip".

I had moderate success in repairing watch LCD's. They don't like water. Sometimes you can take a pair of polarized sunglasses and rotate them and the image will come back through the polarizer. At one point I found the polarizing material.

In a Seiko watch I really loved had a non round watch crystal. I had the ability at work to actually cut a piece of quartz on a diamond saw and make a watch crystal.

There is a Timex close to the Seiko, so I have to settle for that,

My problems were not the connector. Once you know how the connector works, you can likely re-position. Just think of fine wires of a certain pitch embedded into insulating rubber. There is other ways of doing the connector too e.g. alternating layers of a conductive elastomer.