Teac X700R Slow Rewind

[tapehead]

I've pulled out this deck I acquired some years ago. I replaced the capstan belt and while play testing the machine, I find the rewind is slow. The rewind was slow before I changed the capstan belt, so I don't think I messed anything up during the belt change. With a full reel on the left side, and rewind, it almost comes to a stop. FFWD works fine. There is no sign of sticky shed syndrome with the tape. I would appreciate any guidance on where I might start looking for a problem. Thanks!

 

[pustelniakr]

Make sure you are threading the machine properly.

After that, ensure that the brakes are lifting properly, then set the reel torques to spec. You will need a service manual. High back torque or low take-up torque would do what you describe.

Also, lube your reel motors. A nice Teflon-bearing lube, like Tri-flow, would serve nicely.

Rich P

 

[tapehead]

Will give that a try. Thanks for the tip.

 

[tapetech]

See if the problem is about the same with the tape not threaded on anything: just reel to reel. If speeds are now perfect, then look into bad guides (last paragraph).

With no tape, put deck into REW and feel by hand or measure the left reel torque (should be around 1100 g-cm). Also at see that the right reel has a small amount of power applied to it and that it spins freely by hand. Now do the same thing but in FF mode.. Measure the right reel torque and then see if the left reel spins freely by hand and has a small amount of power applied. REW and FF should be similar.

If the REW has noticeably less torque than FF, then the motor may need servicing. It has to be carefully taken apart and the commutator gaps cleaned out. Always pull the brushes away from the commutator with a piece of wire before removing the armature from the bearing.

There is no adjustment for reel motor torque.

If the motor mechanics is good, and the motor is still weak, then the motor drive circuit needs repair.

Also make sure that none of the guides have tape oxide deposits in the corners. This can trap the tape. Clean the guides with acetone if dirty.

 

[tapehead]

Thanks for all the tips. I got the service manual from HiFi Engine, as as tapetech mentions, there is no adjustment for torque. The brakes are immediate and strong. Meanwhile, I tried a different tape (1.5 mil), paid close attention to properly threading it and ran through a few cycles of FFW and REW from start to finish. The problem seems to have gone away, although in both directions there is a bit of speed decay near the end of the tape, but not a hindrance in my mind. Either I had the first tape threaded improperly or the first tape I used was the problem. Having not played these tapes in years, I suppose a takeaway is to FFW and REW prior to play to loosen them up. Thanks again to Rich and tapetech for the benefit of their experience.
Mike