Hi looking for Schematic on Touch Panel Connector to troubleshoot hardware issue

If anyone has a schematic or better yet troubleshooting/service manual for XT875 would be greatly appreciated. My touch screen isn't working even after replacement and I think it has something to do with motherboard connection and need to check voltages/pin assignments. Any help very appreciated...I have had this phone for 4 years and hope to have it for another 4...

Scott