Screen re-calibration?

[Tekuro]

It was set to automatically

 

[linden]

My Tomtom GO720, tactile possition are changed!! Please help me to reset it.

Thanks.

can you give key by key instructions for xl one

 

[oldfogy]

It is not possible to give a key by key set of instructions because all satnavs are not the same.

If you go to Post No 28 on page 2, copy, paste, print it out then read at least a couple of times before starting the process.

 

[ChrisH]

Hey Oldfogy

Many thanks for your instructions above. Worked fine, very easy, methodical. Brilliant. A little bit of patience and iterative adjustment and viola!

My starting was 835 208 668 329 and finishing was 885 398 668 329 on a Go750

I used the tip of a ballpoint pen, gently, and calibrated very closely using the letter keys in the address area of "navigate to"area.

I could touch within a letter box across and up and down to fine adjust. Worked well. I adjusted in units of 40, then 20 and then 10. I found 40 units equated to about two letters of movement on the keyboard when shown on the TomTom.

I found adjusting the right hand side 1st and then the left hand side was optimum. I had only a problem on the x-axis.

Nice that guys like you have the time to write up an easily followed protocol. Made my TomTom useable again. Thanks!!

 

[aurino]

Thank you for the instructions. It worked well.

My starting was 228 829 319 659 and finishing was 730 180 700 450 on a XL-335

Thanks!!

 

[pyor66]

@Niranjan
Are you saying that when you press on the screen, it is selecting the wrong thing? If that is correct, you can try adjustment using a special calibration file in the root of your device. Can you tell us what is being selected when you press various places on the screen? Is everything too high or two low or left or right or ???

An adjustment can be made by placing a file called cal.txt in the root directory of your 720. All firmware versions since 8.051 require the sequence in this order:
MaxX MinX MaxY MinY
(where X = left/right and Y = up/down)

For Left/Right calibration:

MaxX affects the LEFT edge of the screen
Increase MaxX - touch point moves to the RIGHT of where you touched
Decrease MaxX - touch point moves to the LEFT of where you touched

MinX affects the RIGHT edge of the screen
Increase MinX - touch point moves to the RIGHT of where you touched
Decrease MinX - touch point moves to the LEFT of where you touched

For the Y axis, the process is the same only in the up/down axis.

I had this same problem with my old GO 740 and had to make some adjustment to access the bottom areas of the screen. My file looks like this:

926 77 830 200

If you press and hold the reset button in the bottom of your unit briefly. Now, press and hold the power button until the screen appears with white text on black background, then you can release the button. You will see a line on the screen that looks like this:

Touchscreen calib. data: 76 932 140 861

Beware! On THAT screen, the data is MinX MaxX MinY MaxY. Don't use that order when you create your cal.txt file! Anyway, this shows you where the unit calibration is by default if there is not any cal.txt file to change it., so you use this as a starting point for your adjustment. If your screen showed the numbers above, that would the same as if you had created the cal.txt file that looked like this: 932 76 861 140

You should create the file with Notepad or another very basic text editor that will allow you to create the file as BARE text and does not require line break at the end of lines.

I had a similar problem with my GO 720 and your solution has helped but I am left with a residual problem that I hope you can advise me on.
I am now able to use the initial screens accurately but when I try to change 'preferences' the upper options operate the lower option and the upper option is inaccessible. Also if I touch the initial screen, I may not go to options but to the last planned route detail etc. Your advice would be much appreciated.
My cal.txt file reads: 929 79 457 57

 

[pyor66]

Finally worked it out. I did not fully appreciate that horizontal and vertical screens are both divided into two sections. By adjusting each vertical section at a time, I have achieved an accurate result. Many thanks, particularly to oldfogy, whose instructions I printed out and led me to success. Using the rounded end of a good quality pencil as a stylus was also a good tip for accurate location of the touch point. It needs 'finger-touch' confirmation for final accuracy in actual use.
My cal.txt file now reads 929 79 285 57.

Very, very time-consuming though.

 

[yanto]

Hi all, don't know if this thread is too old but have read it all, some really good info here.
My problem is I have a Go720 and removed the ribbon screen cable to fit a new battery, put it all back together only to find the touch screen now working, the screen lights up but pressing anywhere on the screen does nothing. Have removed ribbon and replaced many times to no avail. Tried reset & even put a .txt file in to no avail. I am lost now.

Any help or suggestions would be great, thank you.

 

[canderson]

It sounds as though something went badly wrong with the flex cable or connector during the battery swap, or (less likely, but always some risk, especially in these dry winter months) that some ESD got to one of the components during the work.

If the screen was behaving normally before the battery swap, the problem will not be one of calibration, and the addition of a calibration file isn't going to fix it.

Does the little tan latch on the flex connector on the board stay down properly when pressed back into place? We've seen a few folks who were a little over-exuberant when lifting the connector, breaking a pivot pin on the latch, and then the latch wouldn't stay in place afterward. Try operating the unit with it apart but with the cable connected, and while holding down on the latching mechanism for the flex cable to see if it really is a cable connection issue. It's kind of a four handed job.

 

[yanto]

I will try your advice, will the screen still show but no touch if the ribbon cable is not in correctly? Can you get a new latching mechanism for these?

 

[canderson]

It's possible to lose video or touch or both if the cable isn't working as it should.
No, you can't get new latches for the flex connector, but we've seen a few folks do some desperate and sometimes successful stuff if they break the latch.
When you flip it back down with the flex cable inserted, if it stays down flat, then it's working as it should. If it pops back up as soon as you release it, or if one end breaks off so that it flops around, then it's broken.

 

[HVDK]

My Tomtom GO720, tactile possition are changed!! Please help me to reset it.

Thanks.

it works also for go 730
my tom tom's problem was : when i touch "navigate to" the button "mobilephone" reacts
extra info :remove your memomy card before start
my factory setting (on the black screen (push more then 5 sec on/off) was 85 931 146 844
after making a file with notepad (save iton your dessktop and move it then to your tom tom)
the setting changed to : 931 85 350 50
it cost 2 hours to fine tune the figures 350 and 50 but my tom tomworks now as new

 

[canderson]

Great to hear that this worked well for you. Yes, it's pretty tedious to really dial in the correct settings. Lots of trial and error, even when you think you know what to do!

What I don't understand is why the resistance of the digitizer drifts enough over time such that the recalibration becomes necessary.

 

[Zelfe]

Hi all,

I have this problem as well. I have a go 630 and i get this problem when i tried to type my secret code. i noticed, for example that when i pressed the 8, the 6 was taken in account. Unfortunately, i was not able to press under the : out of the screen...

I created the cal.txt but i am not ble to estimate the changes i have to do : when i staart my tomtom, i get the disclaamer screen with the only button "agree" in the under right corner of the screen. So i cannot really see where my pressure act.

my original calibration was 82 928 130 844

can someone tell me wich number i need to change? i guess i have to increase minY but how much? 5 by 5 until it works?

Or do i have a way to bypass the disclmer screen to acces my secret code screen again, so i can see what the changes i make in cal.txt do?

thanks in advance.

 

[canderson]

It sounds as though you are getting enough feedback from your attempts to press your code numbers to have an idea of where to go.

I don't recall the exact layout of the numeric entry screen for the PIN code. Can you describe it for me? I do not have a PIN set up on my 740 device, and can't recall how it's laid out.

 

[pyor66]

Hi all,

I have this problem as well. I have a go 630 and i get this problem when i tried to type my secret code. i noticed, for example that when i pressed the 8, the 6 was taken in account. Unfortunately, i was not able to press under the : out of the screen...

I created the cal.txt but i am not ble to estimate the changes i have to do : when i staart my tomtom, i get the disclaamer screen with the only button "agree" in the under right corner of the screen. So i cannot really see where my pressure act.

my original calibration was 82 928 130 844

can someone tell me wich number i need to change? i guess i have to increase minY but how much? 5 by 5 until it works?

Or do i have a way to bypass the disclmer screen to acces my secret code screen again, so i can see what the changes i make in cal.txt do?

thanks in advance.

Go to post #28 on page 2 by oldfogey. It is a detailed summary of how to recalibrate a screen. Print it out. It helped me enormously to solve a very difficult problem. The process is very time-consuming, so have plenty of patience.

Quite why TomTom allows this complex problem to persist beggars belief. More especially as my problem arose after an 'update'! Seems like careless programming.

Best of luck.

 

[canderson]

@pyor66
It's a matter of the aging of resistive digitizers. Some do, and some don't, but what happens is that the resistance of the material changes a bit over time, and unless the device is made aware of it, it begins to sense touch as being in different places than it appears on the LCD screen. I have a 740 that required a tweak to properly register the bottom of the screen, and I also have a much older 720 that has never required any modification. It's a bit of a crap shoot, it seems.

As the manufacturers of these devices say, "The polyester coversheet expands and contracts with temperature and humidity changes, thereby causing long-term degradation to the coatings as well as drift in the touch location."

 

[pyor66]

@pyor66
It's a matter of the aging of resistive digitizers. Some do, and some don't, but what happens is that the resistance of the material changes a bit over time, and unless the device is made aware of it, it begins to sense touch as being in different places than it appears on the LCD screen. I have a 740 that required a tweak to properly register the bottom of the screen, and I also have a much older 720 that has never required any modification. It's a bit of a crap shoot, it seems.

As the manufacturers of these devices say, "The polyester coversheet expands and contracts with temperature and humidity changes, thereby causing long-term degradation to the coatings as well as drift in the touch location."

Thanks canderson. That's interesting. As the problem arises from the properties of materials we clearly can't blame TomTom. But it still makes life hard!

Regards.

 

[Zelfe]

It sounds as though you are getting enough feedback from your attempts to press your code numbers to have an idea of where to go.

I don't recall the exact layout of the numeric entry screen for the PIN code. Can you describe it for me? I do not have a PIN set up on my 740 device, and can't recall how it's laid out.

Hi, thanks for yoyr answer. The numeric entry is 2 lines of digits located at the bottom of the screen.

But my problem is that i do not have access to this screen anymore. I only have access to the disclaimer screen, like just after an update, with the "i agree" button in the lower right corner of the screen. As this button is located in the bad area, i cannot even see if the changes i make in cal.txt are better or worse...

 

[billv]

Many thanks to everyone who contributed to this thread

I have a GO 950, I followed the instructions and managed to calibrate the screen.
With my TT to get to the screen with the cal data
I had to keep the power button pressed for about 10 seconds.

The factory cal data was 318 729 342 649
and the new Cal data is 160,629,342,649

I rearranged the order of the new data to 629 160 649 342 for the text file

This is one thing which was pointed out earlier but it can be missed.
The cal data shown in the TT screen is in different order to the data we enter in the text file.
My GO 950 screen was showing them in this order
MinX MaxX MinY MaxY

And the text file expects them to be in this order
MaxX MinX MaxY MinY