OESF Portables Forum

Everything Else => Model Specific Forums => Distros, Development, and Model Specific Forums => Archived Forums => SIMpad forum => Topic started by: tombraider on January 13, 2007, 04:50:01 pm

Title: Touchscreen Suddenly Doesn't Work On Simpad
Post by: tombraider on January 13, 2007, 04:50:01 pm

I have the device disassembled but don't know what to check to fix the touchscreen.
I've touched and wiggled just about everything.  Even disconnected the battery for a while in sheer desperation.

Stylus touch DOES work a bit.  It works only on certain areas of the screen but even right after calibration,  the touch spot doesn't correspond to what happens and NOTHING happens on touching the right side of the screen.

I CAN hear some kind of sound of a solenoid?? switch whenever the screen is touched.

Is this just a lost cause?

I even reflashed with Familiar to see if it was a software problem but the touchscreen works neither in Win CE nor in Linux.

Expert help needed.  

Title: Touchscreen Suddenly Doesn't Work On Simpad
Post by: lpotter on January 13, 2007, 11:56:54 pm

I have one that the digitizer went wonky and I cannot calibrate it anymore. Gives bad points that are all over the place. It just gathers dust now.

Title: Touchscreen Suddenly Doesn't Work On Simpad
Post by: tombraider on January 14, 2007, 10:57:59 am

Quote

I have one that the digitizer went wonky and I cannot calibrate it anymore. Gives bad points that are all over the place. It just gathers dust now.
[div align=\"right\"][a href=\"index.php?act=findpost&pid=151138\"][{POST_SNAPBACK}][/a][/div]

Thanks,  that's what I thought...sigh.  

Title: Touchscreen Suddenly Doesn't Work On Simpad
Post by: scholbert on January 14, 2007, 11:47:20 am

Quote

I have one that the digitizer went wonky and I cannot calibrate it anymore. Gives bad points that are all over the place. It just gathers dust now.
[div align=\"right\"][a href=\"index.php?act=findpost&pid=151138\"][{POST_SNAPBACK}][/a][/div]

Hi,

there might be a chance to solve these problems more or less quite easily.
From my experience most touchscreen problems are caused from mechanical/electrical issues and are not necessarily software dependend.
Of course there some issues with calibrating and sensitivity using older distributions. But this has been fixed!

So have a closer look at the touchscreen unit of your device.
Sometimes the flex cable that connects the touchscreen unit with the Simpad mainboard maybe affected by corrosion or other mechanical damage.

I once bought a Simpad with a quite damaged touchscreen and was able to fix it with some kind of conductive lacquer that can be used to fix electrical connections.

You may do some measurements with the unit first.
Measuring between contact 1 <-> 3 and 2 <-> 4 should deliver constant values of about  500-600 ohm.
If these values vary extremely, or one connection is completely broken you might try to fix the contacts carefully with a conductive lacquer coat.
But be very careful you might damage it completely    !

Hope this might give you another idea, what could be wrong.

Greets,

scholbert