Nakamichi 600 repair question

Looking for troubleshooting/repair info on a Nak 600 that when warm simply kicks out the play button and stops advancing the tape when about half to two-thirds of a tape has passed. Does anyone know if still has archives that can be accessed? It won't respond to my efforts and the guest page hasn't had posts for months. :-(
Call Jeffrey at ES Labs, there is nobody better.
I'll second the Jeff Galin at Electronic Service Labs recommendation.He is "Mr. Nakamichi." And a nice guy as well!

Good luck with your repair.