Variant J of the PG12864 graphic LCD module is described in this 90.1 KB PDF datasheet. The part number corresponds to a 128 by 64 dot display, and the sheet should list interface pins, bus timing, supply requirements and the mechanical outline. When servicing equipment with a faulty or cracked display, a technician uses it to confirm wiring, measure contrast voltage and evaluate substitutes. Other lettered variants in this series differ in size and pinout, so the J marking on the module must match.
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 @acodis_lcd_datasheets_EDID. Enginerys does not host this file.
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