All resistors in digital inputs are grouped in chips. You need to start debugging when you know what is not working. Following the wrong signal and measuring with avo-meter and oscilloscope you can describe part of the plate. Reading parts signatures you can exactly restore schematic and functional of this part of the plate.
This is not new but you need qualified electronic engineer.
In my case R-matrix has one broken resistor. The real problem was that resistor can be measured and was slightly out of tolerance. But not working actually.
As a result Lotem report that input clamp arm does not reach home position.
Sorry for the ugly english.