Know anything about cassette players?

Hi all.

My family has had this Kenwood Stereo Cassette Deck (model KX-830) for a while now, but after it sitting for so long with no real use it turns out some things no longer work on it.

The machine powers fine with no sparks, blown fuses / bulbs. The pots are a little crackly but that can be easily cleaned up with some deoxidizer. My worries instead come from the cassette player itself.

The only motor / cassette spinner (sorry if I sound like I don’t know what the proper terms are – I don’t know what they are) that seems to be working is the one on the right side. The other does not move at all. Fast forwarding, reversing, and playing all work fine on the right side, but again no movement on the left. The left-motor spins freely when I move it with my finger, but not otherwise. Putting a tape in and attempting to use any of the features mentioned above simply lock up the tape and stop shortly after.

I suspect this has to do something with the old belts getting worn and are no longer working, or that a motor no longer works. But I am new to Hi-fi equipment and especially electronics from this age.
If anyone knows anything about what could be going on, and especially if you have any info about how I should replace any of these broken / old parts, let me know. I’ve found a user manual on hifiengine for this model if it is of any use.

I’m excited to try to get this thing up and running smoothly since I have some spare time quaratining and all.

I asked a friend who is big into cassettes and she said you should probably check and replace the belts