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How to spot a reproduction cartridge
Reproductions have gotten good enough to fool a quick glance. The label print is usually the first tell — genuine Sega labels use a specific glossy stock and the colour registration is dead accurate. Reproductions run slightly duller or the colours bleed at the edges.
Open it up if you can. Genuine boards use Sega-specific screw heads (usually a security bit, not a standard Phillips) and the ROM chip markings match known part numbers. A generic flash chip glued in is the giveaway.
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