Weird one this. I can't complain as I've had the board over 7 years now and it's been trouble - free up to this point.
It was working perfectly one night, then, next day, started up and no response from touch screen. I manually entered the calibration menu but of course there was no response from the top or bottom squares.
I then entered the diagnostic menu and ran the LCD test. Once I got to the screen with the three blue squares it was evident that there was no signal transmission for the Y axis. X axis does respond but not greatly.
(see attached image).
Again it was not possible to complete the calibration process.
At this point I began to dig a little deeper. Being a resistive touch screen it can be simply tested for continuity with a DVM.
Next I very carefully stripped down the screen surround to expose the small junction PCB which is taped to the right hand side of the LCD panel. I unplugged the loom for the digitizer and no surprise, good response on the DVM for the X axis (resistance changes nicely on the DVM when touching the screen), but the Y axis is completely open circuit !! - this appears to correlate with the results of the diagnostic test.
Just to be on the safe side I unplugged the white 4-way ribbon from the SCAN ADC board and checked continuity of that to the junction PCB and all is fine --- so --- I have to conclude that digitizer is 100% toast.
I gather it's a Fujitsu N010-0554-T347 which can still be purchased from 3rd parties. I'm based in the UK I'm going to try Mouser Electronics
http://tinyurl.com/oqo8as2
Unless anyone can suggest a better contact in Europe?
Wish me luck!
Dave.
