i'm compiling a counterfeit transistor identification guide. i've seen a lot of these in the last few years, and the counterfeiters are learning from their mistakes. these transistors are usually knock-offs of popular audio output transistors (such as the 2SA1943 and 2SC5200) or TV horizontal output transistors, or any other semiconductors that are normally in the medium-to-high price range ($5.00 US and up).

generally these devices are cheap devices bought in bulk, then have their original part number removed, and have it replaced by a part number consistent with a higher current/voltage/wattage device. for instance an audio output transistor rated at 200W, 300V, and 15A is counterfeited by taking a similarly packaged transistor (MT100 case style) that is only a 150W, 200V, and 10A device. the original part number is shaved, sanded, wire-wheeled or chemically treated to remove the original ink, or in some cases painted black to cover up the original number. the new number...