Touchscreen circuit page from the Samsung SM-A03 schematics, delivered as a PDF of 2.80 MB. It shows the touch panel connector, its supply voltages and the communication lines, which is the place to start when touch is unresponsive, erratic or works only in parts of the screen after a display replacement. Measure the rails at the connector, check the protection and filter components and confirm the flex is seated correctly. Open it with any PDF viewer and match the phone model before relying on it for repair work.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @phoneSchematics. Enginerys does not host this file.
How to open a .pdf file
The standard format for schematics, block diagrams, power-sequence charts and service manuals.