SIM card reader schematic for the Samsung SM-A21s, PDF, 3.81 MB. The page covers the SIM socket circuit, usually its supply, clock, reset and data lines plus protection components. It is the reference to use when the phone shows no SIM or loses the card intermittently: check the socket pins, measure the SIM supply during detection and inspect the protection parts for damage. Opens in any PDF reader. Verify the board is the SM-A21s version before matching designators.
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.