Question JVC cassette deck won't stop at the end of a tape

[LeeDerbyshire]

My 80's JVC cassette deck no longer switches off at the end of a tape. I found a small metal plate next to a solenoid that disengages the mechanism when pressed, so my guess is that something is failing to activate the solenoid. But beyond that, I'm stumped.

 

[hang-the-9]

There is a short colored tape lead that a sensor sees to mark the end of playable media, could be that sensor failed.

 

[LeeDerbyshire]

Oh, I didn't know about that. I suppose this is in the area of the heads, like most other things? Does it use a light source? I've never noticed anything like that, but I suppose it'd need to be very dark to see it.

 

[hang-the-9]

Actually I may have been wrong about the audio cassette with the tape sensor, it may have been VCR tape that has is

This shows that it uses pressure to drop down an arm to stop the gear https://www.cse.iitk.ac.in/users/amit/courses/371/adarsh/contents.html

 

[LeeDerbyshire]

ISTR that VHS used a light as a dew sensor. My first thought was to look for a small moulding that pushed into the tape, and detected when it got tight (I've seen such on many portable players I've owned), but I can't find any trace of one. Maybe that's why it stopped working? OTOH, I would surely have found it in the case if it had dropped off, or would be able to see the metal arm that held it.