Code 5100 means the print carriage can't move freely — usually an obstruction, packing material, or a dirty encoder strip.
Work through these in order; most people are fixed by the first two or three.
On new units, remove all orange tape, foam and the cardboard near the carriage.
With power on and cover open, move the carriage and remove any jammed paper or debris from its track.
Gently wipe the clear plastic timing strip behind the carriage with a dry lint-free cloth (no alcohol) — ink smears here cause 5100.
Reinstall cartridges firmly, close the cover, and power-cycle.
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