Archive of 4.19 MB labelled PM-A-HPC-S MV-MB-V1, likely a sibling of the PM-I design with a different variant letter. No brand, model or document type is stated, and V1 seems to mark a first version of the main board. Open the ZIP to identify the contents, and compare every marking with the board on the bench, because related variants can differ in components and rails. Schematic material like this helps trace voltages, inspect controller circuits and locate test points.
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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