I have a Nakamichi 700 Mk 1 cassette deck. Everything works fine apart from it chews tapes after about 10 minutes of playing. Afer a few minutes of playing, a loop of loose tape is generated between the capstans. This eventually wraps itself around the capstan. I have replaced both the centre belt & capstan belt but its made no difference. I understand that the machine is designed to maintain tension across the heads. This implies that the pulley/flywheel for capstan 'A' (part no. CA-5006) rotates faster than flywheel 'B'. I have measured the diameter of the pulley for both flywheels. Pulley 'A' is 47.20mm diameter and pulley 'B' is 47.00mm diameter. Therefore pulley 'B' will rotate faster than pulley 'A' and a loop of tape is bound to form between the capstans. Where am I going wrong? Can you help? Calum (UK)

Hi PuerkoNess,



The motor appears to be fine. There are no funny noises from the mechanism but both flywheels do appear to be running eccentrically by the tiniest amount - flywheel B being the worst. There is no discernable play when trying to wiggle flywheel A from side to side but there is the slightest amount of play between the capstan shaft and bearing on flywheel B. Is this likely to be the problem? If so, are new Capstan Flange Holder Assembies available (part # CA-5160)? Thanks. Hi PuerkoNess,

The motor appears to be fine. There are no funny noises from the mechanism but both flywheels do appear to be running eccentrically by the tiniest amount - flywheel B being the worst. There is no discernable play when trying to wiggle flywheel A from side to side but there is the slightest amount of play between the capstan shaft and bearing on flywheel B. Is this likely to be the problem? If so, are new Capstan Flange Holder Assembies available (part # CA-5160)? Thanks.

Thankyou all for your help. I have just resurrected the Nat after a 12 year layup. Same problem...naturally - as I haven't doe anything in the intervening 12 years. I have made do by applying 2 layers of insulating tape around the supply side pulley. This now has a diameter of 47.36mm. Tension has now been (artificially) restored across the heads and everything is working fine! Even recordings are OK. Prior to utilising the insulating tape both job the Nat would not record at all. It is obvious now that the tape didn't have enough tension for it to make proper contact with the record head. Nevertheless, one major concern remains......how on earth can this machine have been produced with a supply side flywheel pulley having a diameter smaller that the demand side flywheel pulley? Thankyou all for your help. I have just resurrected the Nat after a 12 year layup. Same problem...naturally - as I haven't doe anything in the intervening 12 years. I have made do by applying 2 layers of insulating tape around the supply side pulley. This now has a diameter of 47.36mm. Tension has now been (artificially) restored across the heads and everything is working fine! Even recordings are OK. Prior to utilising the insulating tape both job the Nat would not record at all. It is obvious now that the tape didn't have enough tension for it to make proper contact with the record head. Nevertheless, one major concern remains......how on earth can this machine have been produced with a supply side flywheel pulley having a diameter smaller that the demand side flywheel pulley?