Touch screen testing

[candyman]

Hi All,
 Does anyone know how to test  touch screen componets? I got a Magical touch game with a bad monitor. replaced monitor(works great), reinstalled touch screen overlay, but it is not registering in all places, and the alignment is way off in the places it does register. I have tried the calibration mode several times, but it does not seem to register in some areas so I can't proceed. I am trying to see if the overlay is bad,controler, or PCB board. I have ohmed out the wires on the overlay corners to controler and they seem fine. It is a micro touch model 175711.
Thanks for any info.
Aaron

[Ken Layton]

Even though they are a competitor, Merit Industries (www.meritind.com) has a good touchscreen troubleshooting section in the tech section and FAQ.

[candyman]

Ken, Thanks for the info. Ichecked there site and found some good testing info. I found one ground wire hidden and not connected, however after  connecting/rechecking problem still exists,  also I do not have +5vdc(pin  4) do you know how/where pin 4 gets 5v, there is only 12vdc input volts for this connector.
                          Pins 1-3 are factory test points/no connection
                          Pin 4 +5vdc
                          Pin 5 p.s. ground
                          Pin6 Chassis ground
                          Pin7 +12vdc input
                          Pin8 Sensor shield, driven w/AC volt.
                          Pins 9-12 wires to each corner of touch screen
Thanks for your help
Aaron           

[Ken Layton]

If the touchscreen glass and controller are 3m/Microtouch, go to their site for additional tech info.