JVC HR-S3500U shutting down after a few seconds?
 

When the tape is loaded (which sometimes works and sometimes gets stuck halfway through and auto-ejects) the player does nothing. Pressing the play button does nothing. The screen sits at Auto.

Hitting the power button gets the tape to play for a few seconds, as the video shows, but then it dies and goes back to Auto.

The stop/eject button works and ejects the tape properly (sometimes).

It looks and sounds like some gears are stuck, but I cannot identify which ones or how to fix it.
The noise is the motor continuing to spin even though nothing is moving.

Check your tapes, they sound sticky to the drum.

I've tried three different tapes, they all behave the same way.

The drum is not spinning free for sure and that requires a qualified technician to take it a part to repair, It is not something that can be fixed over a forum posts unfortunately.

As latreche mention , if something sticky
Is on the head it will create an issue no matter what tape
You put in.
Heads need cleaned then proper way. Any belts slipping on pulleys?

I fixed it. It was the mode switch.