Schematic for the PMA400 Lambda amplifier, a 400 W audio power amp design credited to Rat Net, supplied as a 477 KB PDF. The name gives the power rating and model but no board revision. Use it to trace the input, driver and output transistor stages, check rail voltages and bias settings, and identify parts when repairing blown outputs. Hobby amplifier designs circulate in several versions, so compare the PCB layout and part values with the board in hand before ordering replacements.
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 @pdf_servicemanual. 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.