How to repair home phone lcd fading/missing numbers

[computer-joe]

I have 4 old home phones that i kept in a box for 7 years,
when i put them in the box, the lcd screens were working fine,
years later when i plugged them back in, the lcd screens are fading/missing numbers

i took it apart but i don't know how to fix it,

is it fixable?

i can still use the phones fine, it's just you can see the numbers and it's annoying

 

[unclestan]

It happened most of the time when my scientific calculator aged, the screen bleeds. Maybe the polarization phase on the screen reduced over time. I'm not really sure if it's repairable though unless you'll replace the screen itself.

 

[Harald Kapp]

This type of LCD is often connected to the PCB via elastomeric connectors (aka ZEBRA conectors).
One issue with these elastomers is that the yneed to be absolutely dry. Moisture can create short-circuits between contacts which is enoughto cause malfunction due to the very small currents involved in an LCD.

Another issue (more likely in your case) is that the elastomer can become hard. When it loses the plastocity, contacts can become open circuit. As your photos show missing pixels, I think this is more likely than issue #1. Check whether this is the case by pressing on the LCD connector (provide I'm right in assuming this type of connector is used). The display should change. Some pixels may turn on, other pixels may turn off instead.
In that case replacing the connector strips should help. You can buy them as spares e.g. on ebay.

 

[kellys_eye]

According to the pictures you post the board-to-display connection is a 'ribbon' type cable - I can see 'tape' holding the ends down. If you power up the display and apply some (light) pressure along the edge of the ribbon - both ends - you may see an improvement in display quality. Careful doing this at the display as the glass is very thin.

These ribbons are (seemingly) a pressure-fit against the board edges - well, if they are soldered then it's a VERY fine soldering technique - but they do tend to respond to pressure. I wouldn't advice trying to solder them either as you will end up causing more damage than you can cure.

If the pressure method helps/works then fit something that can maintain the pressure with the case assembled - stiff sponge rubber or the likes....

 

[computer-joe]

I pressed the ribbed in different spots, and i did see a slight improvement, but not overall in all of the lcd, only in some parts

the ribbon seems like its some sort of tape,

i ripped it by mistake, it came off the lcd, and i saw where it connects,

there is no way i will be able to get it back on, i dont even know how they put it on, it doesnt look like sodering , it looks like glue or something, the connections are so small

well now the lcd doesnt work, i still have 3 other phones, but i dont think i will be able to fix it,

its a shame they didnt last, espcially when i barely used the phones, what junk phones!
i hate when things break

 

[kellys_eye]

The contacts on the LCD are very thin and delicate 'depositions' of conductive material and, as you have discovered, easy to tear! No way to repair them either....

Such is life!

 

[unclestan]

I see, so it's actually beyond repair. But that's a really good explanation.