Nakamichi RX-202 continuously flipping tape A to B to A after changing the cam motor belt

[anti-doom]

My Nak RX-202 keeps flipping A to B then to A after changing the cam motor belt. Turn it off then turn it on, tape will stay in place and plays well. Adjusting the CAM A and CAM B per service manual did not help. Please help me. Thanks.

 

[Artie]

I usually associate this type of action as a result of the deck thinking the tape has hit the end. I can't remember how it's sensed on this deck, but its usually either by the index counter not going, or one of the reels not turning. Nak's were famous for having a wonky idler wheel driving the reel tables. Watch the reels closely as the tape gets to the end of side A, and see if either reel, or the counter, doesn't "go" after it reverses.

 

[needforspeed]

Need to change all the belts and the idler wheel, I used this kit, Came with very good instructions
http://www.wjoe.com/vintageandantiques.htm#naka

 

[anti-doom]

Thanks for the inputs. It works fine and plays the whole side of tape without any problem so I think idle tire is fine.Reels are running. Excellent sound. The counter runs. Both belts were replaced with new ones. It still keeps flipping the tape back and fort between side A and side B. Shut it off then turn back on, hit PLAY then it plays fine. As soon as I hit EJECT button or REVERSE button, it starts flipping the tape.

 

[needforspeed]

Thanks for the inputs. It works fine and plays the whole side of tape without any problem so I think idle tire is fine.Reels are running. Excellent sound. The counter runs. Both belts were replaced with new ones. It still keeps flipping the tape back and fort between side A and side B. Shut it off then turn back on, hit PLAY then it plays fine. As soon as I hit EJECT button or REVERSE button, it starts flipping the tape.

The belt in question is in the very back of the transport, Transport needs to be removed for access

 

[kermit z]

If the belt and idler tire have not been replaced, this is where I would start. I did not have that issue with mine, but it was in need with slow playback.

 

[anti-doom]

I think I find the issue. The shaft of the pot with white plastic gear is broken. The gear is completely off from the pot. When the gear is moving, the pot is not (due to broken shaft) so the tape keep flipping from A to B then to A continuously. Not sure if the gear is supposed to be free from the pot or supposed to be attached to the pot via the shaft. If it is the latter, then that is the issue. Any idea? Thanks.

 

[perryinva]

Yes, that is your problem. The pot provides position feed back. Gear is supposed to be attached to shaft. Nylon shrinks with age, and they are press fit on to the shaft, such that if the gear is cracked through, then your screwed. You said broken shaft, (metal) but I assume you meant gear. A pic would help.

 

[anti-doom]

It is the metal shaft that was broken. I am looking for the replacement now.

 

[anti-doom]

Also, what size of the belt that runs that gear?

 

[athanor]

More then a year posted, but in case it is useful for anyone.. The pot must be centered. There's an almost invisible arrow in the plastic of the gearwheel of the pot. Remove the four screws that hold the metal structure of the pot in place. Gently pull up that structure without removing the rubber belt of its position, but enough to rotate the plastic gearwheel of the pot (assuming that the belt is in good condition). Center the arrow in the middle of the hole of the metal structure where the pot is attached. Do this with the cassette plate totally out and the cassette holder rotated half way. Then just lower the metal plate and screw it back in place. After, don't forget to adjust VR503, VR502 and VR501 according the the service manual.

Cheers