ZIP archive of 6.38 MB for the PSCSEE board, marked AR10SU-CU, revision 2.1. The name does not say which brand or which document type it contains, and these codes are not expanded here because their meaning is uncertain. Compare the board markings and the 2.1 revision on the PCB before using it. A package of this size usually holds a schematic, possibly with a boardview, which is useful for tracing power rails, checking a short to ground and locating test points and components.
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 @ITHINKHS. Enginerys does not host this file.
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