Nad 6100 Cassette Deck plays a few seconds just fine then stops


Thanks in advance for any help. I just bought this and the head looks good and the rubber wheel thing spins and is nice. But, I tried 3 tales and each plays a few seconds and then the deck stops itself. When I pull the tape out, it has a tiny loop about 3/4 inch high that did not go into the rest of the shell like it should. I guess there is something that needs to make the tape wind up that is the issue. The sound is clean for the fee seconds and the unit is in great condition. Even came with the box. It is the 1988 version. I think there is only one belt in it and I am not scared to try to fix this. Please help if you can and advise me as to what I can do. I really like this new toy and am excited to get it working right. I won’t test anymore until I get some answers, but its behavior is consistent. Thanks in advance!
chapin99
Progress!  That is, enough progress to be hopeful, but not there yet.  My 6100 deck's no-play problem was due to a loose flat belt on the combined mechanism that provides both play-spindle rotation and roller rack positioning.  I was able to test this via a bit of rubbery subterfuge, which quickly gave out.  At the moment, I've unmounted the tape mechanism loosely to get some leeway to work, but it's still the devil to wind the new belt into place with only two hands.  By tomorrow I should have this running; will report again then.   
Nearly there.  The new belt gets the mechanism working properly.  Belt fitment: between the flywheel hub and the mechanism frame, there's a tiny gap up against a gray nylon "keeper" hub; the hub doesn't connect to the flywheel axle, it just holds it away from the frame.  I could just barely slip the belt thru that gap; then the rest of the belt could slip past the motor hub.  Reversing that let me install the new belt.
However, in "Play" there was an insistent, regular blip-blip-blip sound under the music.  I replaced two of the power supply caps and it went away, so I'll replace all the PS caps, hoping that'll do it. Really, the playback quality is quite good at this point, yay.  
OK, final report on fixing my NAD 6100 cassette deck (from eBay as a Part/Repair Unit).  The problems: no FF/RW/Play, and a repetitive "blipping" sound once Play was working.  
My repairs:
  • I used electronics cleaner and lube sprays in the motors, tape path, and behind the button control contacts, plus "working" them through several cycles.  That got the buttons and the FF/RW working.
  • Replaced the worn flat belt.  That restored Play function, but playback had an electronic blip noise and lack of clarity.
  • Replaced all the caps on the PS board with good Elna and Rubycon caps.  That removed the background "blipping" noises.  I believe it also restored the fidelity of the playback quality.
Auditioning: wow, do I like this deck now.  Having a rock-solid tape mechanism paired with Dolby HX-Pro and Tandberg DynEQ, it offers superb playback quality.  This 6100 has detail retrieval, soundstaging, and tonal fidelity better than any other tape deck I've had.  Again, wow.