I recently got given the fun task of repairing the broken screen on a car diagnostic scanner. Its a 7" colour LCD display with a 4 wire resistive touch screen digitizer overlay. I thought it would be fairly straight forward, which is why I opted to carry out this repair myself....sadly its proving to be a bit of a pain in the ass.
The display was easy to replace, I just plucked it out, got the numbers off the back and fitted an Ali-express replacement, all good. Unfortunately the touch digiziter was also damaged, it was not labelled so I matched a replacement unit (also from Aliexpress) from the dimensions and wire placement, but upon fitting I found that the X axis was inverted - press the top left corner, the top right is activated and vise-versa.
The device runs some form of Windows CE 5.0 and the simple calibration tool does not allow this fault to be fixed.
The question is, why has this happened? Is the touch screen faulty or is it the incorrect unit? Doing some reading, seems like its not uncommon for these units to have the inverted axis fault, a RMA replacement fixes the problem. More to the point, is there any way to distinguish between different screens? Is there even a difference or do they share a common "standard"?
Or is it possible to switch the polarity of the X axis wiring? I'd love to try it but the last thing we need at this stage is to let the smoke out of something.
A genuine replacement is going to be about $1,000 shipped so not really ideal. I'm nearly there with it, just need to get the touch sorted and I would've got the job done for less than 300 bucks.
Hopefully an expert can shed some light on my dilemma.
Trusted
