I still have and use one!
I have had one since 1983 and it is still in my main rack although I don't use it that much admittedly. I do have many cassettes I made when I did college radio that are irreplaceable. In about 1990 I had a motor go and it was replaced at a local store in Hartford for about $50. Otherwise, bulletproof and it used to get heavy use for about 10 years. The play button should be a cheap fix if you can find the parts. See if HK can help you.
At the time I think I paid about $200. This was the least expensive deck that offered the new Dolby C. There were four models 191, 291, 391 and 491 which added additional heads and better bias equalization. They had a good reputation. The competition was Nakamichi which was more expensive. You had to pay more than $300 to get a Nak with Dolby C. I had a less expensive Onkyo which failed about two weeks after warranty prior to that. Onkyo made a higher end deck with a built in oscillator for bias equalization that was perhaps the best nonprofessional cassette deck then.
Of more help I STILL HAVE THE MANUAL and could send you a copy if you wish. Good luck.