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 ...

[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 ?