Large 962 KB PDF for the LM324P, the quad operational amplifier in a plastic DIP package, as the P suffix commonly indicates. Filed under schematics, it is a part datasheet with pinout, supply range and application circuits. The LM324 runs from a single supply and turns up in power supplies, chargers, audio and sensor circuits. With the pin diagram you can measure each amplifier's inputs and output to locate a dead channel. Surface-mount versions share the pinout, so confirm the package against the board.
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 @cyberlanelectonik. 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.