Remove or reduce a screen noise

junglemike128 · #1 07-11-2004, 09:49 AM

Hi everyone. You hear this high pitched noise from you pda screen? In some cases this noise can be really distorbing.
I cannot read for a long in silence because the noise drives me crazy.
OK, so Opening my zire71 once again (i opened it at least some 100 times) i tried to look for the problem and if it is possible - to solve it.
Anyway, i do NOT recommend following these steps, consider them as demostration only. First , if your device is under warranty -

PalmOne DOES replace the units this the abovementioned defect. Also this operation is very risky, you can destroy your screen of whole

pda in second. Anyway, here's the process:
_MY_ zire looks a little bit different from inside :-), but it shouldn't bother you , it's not related to the problem anyway.
OK, so let's open Zire71:
http://forum.ladoshki.com/images/inp...12d37e4f95.jpg
After removing the blue protective plastic it looks like this:

http://forum.ladoshki.com/images/inp...12db4c0461.jpg
Next stage: - pull out the main board and unplug the cable which connects board to screen electronics.:

http://forum.ladoshki.com/images/inp...12e4279b71.jpg
Well, after experimentig a little i found out that nois is NOT coming from this small pcb on the creen. I tried listening the this small pcb from

both sides. No noise. The nois is also has notheing to do with backlight. Look at the previous picture. The most left small connector - is a

backlight. After disconnecting it - noise continues as before. Nois is coming from the surface of the screen itself and almost zero at the

screen's back. So let's unplug the screen itself:
http://forum.ladoshki.com/images/inp...12f5f5809c.jpg

Thisi is how it looks from the side. The bottom lair - is a digitizer which registeres your taps.
http://forum.ladoshki.com/images/inp...12fc79229b.jpg
The digitizer in all such Transflective screens is soft, unlike previous palm V , VX, and palm III, also other models.
After experimenting a while with digitizer i found out that if you raise a digitizer just a little bit - 1/3 of mm - the noise almost stops.

I had to experiment powering the unit in disassambled condition , which is a bit risky:
http://forum.ladoshki.com/images/inp...133bb8808c.jpg
Ok, so let's eject the digitizer very carefully:
http://forum.ladoshki.com/images/inp...130b441313.jpg

http://forum.ladoshki.com/images/inp...13106f0176.jpg
After completely removing the digitizer, the picture looks like this:
http://forum.ladoshki.com/images/inp...1316b35fff.jpg
Than let's cover the screen with regular FOIL, all of the perimeter, including graffiti area.
http://forum.ladoshki.com/images/inp...131d5554ed.jpg
When finished, it looks like this:
http://forum.ladoshki.com/images/inp...133cf44117.jpg
Now put the digitizer back, you can even notice, that in the left bottom corner part of foil can bee seen. Don't worry, you will not
see it in assembled state.
http://forum.ladoshki.com/images/inp...1344801fb5.jpg
Let's connect the screen and check that everything is working.
http://forum.ladoshki.com/images/inp...134bab1812.jpg
Assemble the screen again, by the way, i also put foil under the small pcb - just in case...
http://forum.ladoshki.com/images/inp...135201e7e1.jpg
After assembling everything back again - let's check that digitizer is working properly.
http://forum.ladoshki.com/images/inp...1357881d29.jpg
Conclusion.
To be honest, i must say, that nois is no Completely removed - but it is very silent and can be heard only when putting your ear near the

screen.

PalmTealLover · #2 07-11-2004, 02:39 PM

Lengthy, detailed and brave. How cool!!

Thank you for that . . . my screen is NOT noisy, but I would undertake the operation thanks to your post, if necessary. Nice to see the details and thought you put in to helping -- God knows I've seen enough posts where people complained about screen noise.

The repair job is similar to soldering a ground wire between the volume and tone pots of an electric guitar to the output jack to reduce static hum, and if that doesn't work using copper foil or conductive nickel paint to "soundproof" the inside electronics cavity of the guitar. I've done it to a couple - never thought it would work on a PDA!! Terrific and good to know.

Great job!!! I'll save that to Notepad if you don't mind, for reference. Why? Because I'm more than likely getting ANOTHER T3 as a spare when the "Cobalt onslaught" takes hold in another couple of months - I'm sticking with OS5 and this might come in VERY HANDY.

Take care and thank you.