Memory card slot schematic for the Samsung SM-A21s, provided as a 3.81 MB PDF. It documents the microSD reader circuit, typically the slot supply, data and clock lines and card-detect signal. Technicians use it when a card is not recognised or corrupts data, measuring the slot supply, checking line continuity and looking for damaged protection parts near the tray. Any PDF viewer can open it. Confirm the device is a Galaxy A21s, since other A-series models use different layouts and 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.