Tape deck repair

I have a 25 year old Yamaha tape deck, always worked impeccably. Have barely used it for 10 years and was all set to digitize some cassettes. Pulled out my old cleaning tape and demag tape, ran it through - now my tape deck only produces the right channel! Any suggestions? Did I hose the head somehow?

Don't know how much cassette digitizing you have to do, but it'll probably serve you better to get a new deck than to start throwing money down the rabbit hole of repairing a 25-year-old machine. And you'll get new heads in the process. They can't be in great shape by now. Of course, if it's only a tape or two, I'd borrow a friend's.

Mechanical things can go screwy almost as easily when unused as they can when used. I'd guess it's a connection, though, more than a head. Probably seized up over time and then got loose when used.