Sanyo Stereo System Dual Cassette Turntable AM/FM Radio Speakers - $185 (Moorhead)

These have been sitting in my parents place unused for possibly the last 15 years or so.
I hooked it up at my place and everything works on it still.
The cassette deck on the right has a loose button on it, and I can not it to hold back on again for some reason.
It can possibly be connected again, but I do not know how to do it.