CF-29E touchscreen troubles

I've been going through all my toughbooks that need to just have the bezels clean out for the touchscreen to work and i have had a very high success rate with getting them to work until I came to the one I am currently working on.

Rather than the cursor retreating to the bottom right of the screen it is retreating to the far right side of the screen in line with where I touched the screen. there is no more gunk left in the bezel cavity that i can see. I don't think standing water is the issue. I don't think it would have standing water because of the whole gravity issue and the screen has been standing up at a 90 degree angle for about an hour. I did put some goo gone on the sides of the screen bezel to get some kind of funky adhesive off but i rinse the panel in warm water and then alcohol.

I'm stumped so any suggestions would be helpful

BTW I'm about to take the PCB out of one of the units with a unresponsive touchscreen and compare it to a PCB from a working unit. I recall ohlip saying something about a possible touchscreen disabling jumper on the board. We will find out soon and I'll pass along what I find

Dan

 

I'd guess there is a bad connection from the screen to the interface.

I think(??) the screen works by having one layer with contacts along top and bottom, and the other layer with contacts along the sides. The surfaces have a conducting but resistive film coating.

When you touch the screen, the two films contact and it's read as two potentiometers, one for X and one for Y.

If one connection is missing, the touch will always appear to be along the opposite edge of that layer where there is still a connection.

 

so more or less a bad touchscreen panel

 

It was nothing more than a super compressed dust bunnies shoved into the abyss between the bezel and the TS. had to take the whole thing apart to get it out

 

You are describing the exact same issue I was having. Cursor all the way to the right and would only go up and down at the extreme right of the screen. I re-installed the OS thinking it was driver related only to find out it was an electrical issue.

I opened the display cover and cleaned the TS contacts by sliding a piece of card stock in and out of the connector where the TS connects to the board. The cardstock had 4 black stripes on it from the connections. I kept replacing the piece of cardstock until it came out clean. I booted the unit and I still had the problem. Since the display cover was still off (while on) I lifted up on the TS ribbon and it started working. I shut down, then I added a couple strips of clear, thin packing tape to the back non contact side of the TS ribbon/paddle connector. Booted up, problem fixed.

 

Of course mine couldn't be that easy. I got this machine in such good shape it was incredible, no dust or junk anywhere. Looked like it lived on a desk.

 

Yeah... I was wondering if the touchscreen ribbon might be broken... BUt as you really can't replace it I figured that was a dead end.... Now I will go take it apart and try it out while moving the ribbon cable and see...

 

Well... It wasn't the touchscreen ribbon cable. Maybe I should say it MAY be the ribbon cable. I took the LCD cover off and moved the ribbon cable around. I touched the screen and the pointer immediately moved to the lower right corner... I moved it back out with the touchpad, then NOTHING! It wouldn't move by using the touchscreen again.

So... I swapped in a known working touchscreen from a 1.2GHz model that I have. The screen was working PERFECTLY before. So I boot it up and the touchscreen seems to work... It just needs to be calibrated. So I start up the calibration and it gets a "Parameter Error".... The only other thing I can think of is that it has a screwed touchpad... But that seems to work fine!

Any ideas?

 

Well... I THINK I have found my problem... The touchpad seems to have a permanent left click going on. When I reformatted it and started with the touchscreen... It works if you touch all over the place (Still needs to be recalibrated) but if you try the drag and drop... It created the dashed-line box. So that means to me that something is wedged under the touchpad and not the touchscreen.

Sound right? The thing is... I already cleaned out the touchpad. I REALLY hope I don't need to yank this thing all apart for the 4th time... I'll really be pissed!

 

Very interesting that you think it's the touchpad because the one that was giving me the exact problem had a pretty effed up looking touchpad. you raised my curiosity up so much that i may go back up to my office tonite and do something about that touchpad. I'll get back to ya'll with my results

Dan

 

Now THAT is a dedicated employee....

I gave mine a break tonight... I'll get to it tomorrow. I did a battery recalibration instead. I let IT do the work!

 

Nothing like a late night of coffee and starring at a computer screen.... ah reminds me of college

 

don't bother taking apart the touchpad to clean it thoroughly, I just did that and the TP looks brand new and there is no change in the reaction of the TS. cursor still hangs on the far right of the screen

 

Well... It fixed my calibration problem. I now have a working touchscreen (After swapping in a good one) and a great GPS system working!

Look for the Touchscreen Cleanout Tip of the Day!

 

Are you guys done with the trouble of non responsive touchscreen? I have only one thing to say when you are cleaning up the siding when you dissamble the whole screen. The dirt and other particle probaly still stick on the side even if you used a high pressurize air as it spacer or dumper has an adhesive that when a certain particle can't be remove by it. I suggest to inpect it thou...ghly and also the thin layer of carbon conductor as it maybe damage or something else on it.

ohlip

 

Teo... When I inspected my screen I was looking at it from the back. While I am aware that there might be something still stuck in there... I could see 99.9% of the rubber double sided tape and there was nothing I could find. Well... At least after I cleaned it all out.

Personally I think it is the ribbon cable for the touchscreen. I am leaving on vacation for a week tomorrow but will check it when I return.