Those of us who have worked with vintage sound generator chips such as the Yamaha FM synthesizers in recent years have likely run into our own fair share of “fake” or “remarked” chips, sometimes relabeled to appear as a chip different than the die inside the packaging entirely. [David Viens] from Plogue has finally released his findings on the matter after 3 years of research. (Video, embedded below.)

The first thing to determine is in what way are these chips “fake”? Clearly no new YM2612’s were manufactured by Yamaha in 2015, but that doesn’t mean that these are simply unlicensed clones put out by another die factory. [David] explains how these chips are often original specimens sourced from recycled electronic waste from mostly environmentally unsafe operations in China, which are then reconditioned and remarked to be passed as “new” by resellers. Thankfully, as of 2017, he explains that most of these operations are now being shut down and moved into an industrial park where the work can be done in a less polluting manner.

The next thing that [David] dives into is how these remarked chips can be spotted. He explains how to use telltale signs in the IC packaging to identify which chip plant produced them, and visible indications of a chip that has been de-soldered from a board and reconditioned. There are different ways in which the remarking can be done, and sometimes it’s possible to undo the black-top, as it’s called, and reveal the original markings underneath with the simple application of acetone with a cotton swab.

We’ve talked about fake chips and how they can lead to hardware failure here before, but in the case of chips like these which aren’t manufactured anymore, we’re not left with much choice other than FPGA or software reimplementations. Check out [David]’s 40-minute look into these chips after the break.

[Thanks Greg Kennedy for the tip!]