Display circuit schematic for the Samsung SM-A21s, PDF of 3.82 MB. It documents the LCD connector and the supply and data lines feeding the panel. A repair technician uses it for no-display, lines on screen or flickering faults, checking the display supply voltages at the connector, looking for shorted capacitors and tracing the interface lines to the processor. Any PDF reader opens it. Make sure the phone is an SM-A21s, as connectors and designators differ between A-series models.
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.