A 231 KB PDF titled with the series token 12CTQ, suggesting a datasheet covering several voltage variants of one discrete part family rather than one exact device. The naming matches International Rectifier conventions for rectifier diodes. A repair technician would consult the ordering table to find the exact suffix printed on the faulty part, then read ratings and the package drawing. Make sure the variant on the board appears in the document before using it to choose a replacement.
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.