restoring liquid crystal display

[willisl]

The liquid crystal displays on both of our landline phones have gone illegible. Is there a way to restore them?

Thanks.

[David Wood]

Have you checked the backup batteries in the handsets?

[David Nebenzahl]

On 5/17/2008 6:23 AM [e-mail] spake thus:

I have the same problem with my El Cheapo digital voltmeter; part of the last digit got creamed when water got sprayed on the unit, and now doesn't display. All else works fine (I can usually just ignore that last digit anyhow). Any fix for this?

[larry]

probably corrosion or the zebra strip lost connection between the pc board and glass lcd. zebra strip is a rubber strip with many thin conductive layers.

you might try a little pressure at the edge of the display first to see if the zebra strip might slide a little and make contact again. there is a very real possibility you might never get the zebra strip back in place if you try the following. does take some practice.

disassemble the pc board/zebra strip/glass lcd sandwich. clean the corrosion at either side of the zebra strip with

50% and/or 100% isopropl). carefully reassemble. The z strip depends on even pressure along it's length to connect the pads on the pc board to the invisible pads on the glass.

__________ ____________ pc pads

||||||||||||||||||||||||||| z strip ___________ _____________ lcd pads on glass

(you're looking at the EDGE of the pc board and lcd)

-- larry/dallas

[David Nebenzahl]

On 5/17/2008 5:24 PM larry spake thus:

[snip procedure]

Yes, I know about those connectors, having taken a lot of LCD devices apart (but didn't know what they were called). And thanks for the suggestion. I think I'll just leave it alone; the chances are that it wouldn't work at all if I tried to rebuild it. I'm pretty sure that is where the problem is as you suggest.

I see that my surplus catalog (Electronix.com) sells those same DVMs for $7.95. Not worth tinkering with.

[Bob F]

But you can learn something by trying.

Even more so.

I hate to see how much easily repairable electronics is discarded because something simple to fix failed.

But then again, I recently got a freeby iPod from a craigslist posting. Ten minutes of googling, and I found how to recover from the error.