Nakamichi BX2 will not take-up tape and play

The reason that a tape player eats tapes is that the take up reel is not turning, There is a sensor that shuts off the machine if the take up reel is not turning. The tape goes between the pinch roller and capstan which pull the tape out of the supply side of the cassette. Since the take up reel is not turning the tape that is pulled out spills into the mechanism of the tape deck, so if it did not shut off about 2 more inches of tape would continue being pulled out of the cassette every second. There is a mechanical problem on the back side of the tape player. A reel, a belt, or a pulley.
If it will not FF it is likely a small belt.

It is problem in Take-up Reel section and its not sending signal to processor. How old is this unit?

Can you elaboate more on the issue

Well two things have to happen to make tape move in a cassette deck. One is the Capstan shaft has to rotate and that is usually a belt link to a motor through a pulley. The second thing is you must have take-up torque. If the tape moves but the take-up reel does not pull it onto the take-up reel then you either have a eaten tape or the deck will shut off. in your complaint it could be any of these items- maybe a bad Idler from the reel motor or the capstan belt is old and stretched.

The reel drive of your set is not taking up the tape and resulting in no detection of reel pulse. this makes it switch over and the result happens again. Please clean up your drives, the rollers, change the belt and check the reel drive arrangement, the motors. I am sure the mechanism must be reset with new belts . This must solve your issue. Good day

Check leaf switches and also, press play -- after a few minutes, feel motor(s) for heat build up. If it gets hot, either motor is bad of something is preventing it from rotating

I had sorta the same problem and I just fixed it. Mine was making clicking noises and jerking the tape causing speed variations and pitch changes, Uggghh. The FF, Rew, and take up functions are not belt driven like most decks. There is a little idler wheel between the motor and the take up axle. Take the whole transport assembly loose from the front of the deck...slide it back 3 inches . Take off the ground wire screw, and 3 screws holding the transport mechanism in place :...1 screw on top, 2 on bottom. Take the black front faceplate off of the drive...2 little screws. This exposes everything.The little idler wheel has a press on tiny,tiny piece of clear plastic holding it onto its little axle. Be hella careful. Use a tiny eyeglass screwdriver to pry it up and off. Dont lose it. Pull the idler wheel off. The rubber has hardened and slips. Pry the rubber rim off of the white plastic pulley using the tiny screwdriver. Put on an O ring that just fits. Scruff up the perimeter of the O ring with 220 sandpaper, Easy does it. Idler wheel goes back in, press on the little plastic retainer, put the black metal plate back on( 2 screws at top), slide the transport mechanism back into the front panel, secure with 3 screws, ground strap, replace cover. Clean heads, demagnetise, badda bing, badda boom.

try firmly banging the cassette onto a table top(with reels flat) a few times, then ff right through and rew a couple of times. this will layer the tape more evenly and hopefully allow the mechanism to play it. the takeup reel or autostop mechanism may be failing if the deck does not have enough torque to carry the tape and may require belts replaced or dried grease removed in the transport.

it has probably thrown the capstan belt and will require a new belt fitted. the transport relies on capstan rotation to engage play. a separate reel motor operates ff/rew and takeup funtions