Synergy is what led Sony to buy Columbia Pictures for $3.4b in 1989. Sony thought consumers who liked its hardware would like its “software”–the movies that Columbia produced. But customers with a Sony VCR didn’t even think to rent a Columbia film, and those who liked a Columbia film never thought to buy a Sony TV to watch it. Somehow, this surprised Sony. Sony wrote off the entire value of its Columbia purchase.

Fast forward to 2006, when Sony tried the idea again, with Sony Connect, a way for customers to download Sony music onto Sony electronic devices. Sony thought it could sell more music and more devices by linking them, but customers thought otherwise. They preferred this obscure device called the, um, oh yeah, the iPod. Maybe you’ve heard of it. For some reason, customers didn’t want to have to carry around a player for their Sony music, plus separate devices for music from other studios. Again, Sony was surprised.

Last summer, Sony tried again. It bought out Bertelsmann’s share of a music joint venture so Sony could have more control over how it will integrate music with its hardware. This, too, will prove to be a bad idea–and not just because Sony overpaid and increased its exposure to a deteriorating industry. I’m betting that Sony will be shocked and dismayed.

For good measure, Sony is running goofy TV ads that tell us that we should buy Sony TVs to watch sports because Sony equipment is used to film the events. Maybe they’re just counting on consumers to be stupid, in the time-honored tradition of advertising. Maybe Sony just wants to burnish its reputation as a technology leader, which is fine. But Sony better not be breathing its own exhaust here. Otherwise, Sony is making exactly the same mistake it made in the ’80s when it decided that it could sell VCRs by making movies.

In investigating 2,500 major failures over the past quarter century for a recently published book, a colleague and I found all sorts of interesting mistakes. We even found a few companies that made the same mistake more than once. But I’m not sure I could name a company other than Sony that has made the same mistake so doggedly.