Graphtec ASSY 51700‑005T is the primary control board in Graphtec’s industrial cutting plotters, handling motor drive signals, sensor inputs, and communication with the host computer. Common failure points on this class of boards include degraded power‑regulation ICs (causing brownouts or erratic motion), burnt capacitors or solder joints at high‑current driver outputs, and corrupted firmware memory that leads to startup errors or loss of plotter control. For a first‑pass diagnosis, verify the 24 V/48 V supply rails with an oscilloscope for ripple spikes, inspect all power‑regulation footprints for signs of overheating or cracked components, and read any diagnostic LEDs or error codes displayed on the panel to pinpoint firmware or communication faults.[oss-gpt-20b]