Hi:
I have never taken apart a B&O video player. However, I have removed numerous jams from other generic players. Unfortunately (for you as you seem reluctant to do so) it is best to take it apart rather than try and pull it out through the flap.
However, from my experience it is a piece of cake and does not require any kind of electronic work.
Here is how:
1. Unplug or switch off the machine from the wall
2. With a screw driver remove all screws to case and lift off (it should slide backwards)
3.. You shoud see the tape in the mechanism - have a look to see if the tape itself is tangled or if the cartridge is just stuck in.
3.. If it does not look like the tape is stuck, you may be able to allow the machine to eject the tape with a bit of assistance
4. Be aware of what you are doing/touching and plug the machine back in. Then press the eject button on the machine and watch to see if the tape is likely to come out (mechanical noises straining would indicate that it might). If it seems that way carefuly put your finger on the plastic tape cartridge (nowhere else) and push the tape out of the tray gently to see if the tape will move out.
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If this will not work, switch the machine back off at the wall.
Find out why it is jammed - if the tape is stuck/exposed, you might want to cut this with scissors (make sure there is no power to the unit) and pull it free.
Then see if you can lift/pull the cassette free.
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Disclamer:
I am not an electronics expert. I am a fiddler. I have some technical nouse and have done this on numerous ocasions when my tapes have got stuck in various machines. To others on the forum this might be the most stupid thing they have ever heard. However, it worked for me. Bear in mind that all machines are different and some tapes are elevated up before being ejected out rather than going straight in. Thus you may have to adapt my method.
Thanks
Graham