Mirrored PCB artwork for a Zener amplifier board, a 237 KB PDF; espejo is Spanish for mirror. A mirrored print is typically used for toner-transfer or photo methods of making a printed circuit board, so it is a layout rather than a circuit diagram. The name does not state which Zener model it fits. Match it with the corresponding schematic, check the print scale against real component footprints and confirm orientation before transferring it to copper.
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.
Any PDF readerSumatraPDFFirefox / ChromeFlexBV (links PDF to boardview)