RTR slow rewind, 3 motor decks

H

Harry Spring

New member
Hi, I am a newbie to this forum and have recently acquired several rtr machines. A few of them are three motor (Akai/Roberts) and I've noticed a general problem with slow rewind, especially when getting towards the end of the spool (7"). This is particularily annoying. I've sort of bypassed this problem by removing the tape from the normal path past the heads, tensioners, posts, tape lifters, and just run between the two reels. I remember years ago when I had a home model Ampex F4460 that DID NOT have tape lifters, it was recommended to rewind or fast forward tape in this manner to save wear on the heads. Anyone have any comments on this? I am thinking that the Akai/Roberts machines probably need replacement motor capacitors to increase the torque thru the motors. I have a couple of 1mfd motor caps and think I will try one of them to see if this helps. Now am also wondering if there is any problem with too much capacitance for the motors caps?? In other words, I would just parallel the 1mfd cap with whatever is already there. Thanks for any help. Am awaiting an A77 Revox to see how it measures up to the Akais and a Pioneer RT707.
 
I would suggest you check lubrication on the rollers and chek the entire head areas for build-up.

I just ran into the same problem wit a deck. Rewind reel to reel was superb but through heads was painful.

Turned out to be an improperly lubricated roller assemby guide for left reel.

Could also be a brake release issue!
 
First question is... what kind of tape are you using, and is it new?

Tape with sticky shed syndrome will cause slow wind and playback problems. Let us know what kind of tape you're using and we'll go from there. :)

Also see the Sticky Shed Help Thread for more info here:

https://homerecording.com/bbs/showthread.php?t=228067

Some of the links in my first post are outdated, but still a lot of good info in the thread.
 
Beck said:
First question is... what kind of tape are you using, and is it new?

Tape with sticky shed syndrome will cause slow wind and playback problems. Let us know what kind of tape you're using and we'll go from there. :)

Also see the Sticky Shed Help Thread for more info here:

https://homerecording.com/bbs/showthread.php?t=228067

Some of the links in my first post are outdated, but still a lot of good info in the thread.
Click to expand...
Being so new to this forum I didn't have any luck trying to find out which type of tape to avoid or would cause problems, but one group of tapes I just got is BASF LP35. Also has number 18 540. Tapes appear to be in great shape and do not appear to be sticking to anything. Heads and complete tape path very clean. Rollers spin effortlessly, especially with the huge flywheels. One thing I did notice with one of the Akai single two-speed motor decks was that at the slower speed there seemed to be a little more torque, but still eventually stopped the closer you would get to the end of the rewind cycle (most of tape on left reel). I hope this BASF tape is good because I like the way it is packaged and is in a fairly airtight plastic container and then within another hard shell case.
 
BASF LP35 should be fine. It's not prone to sticky shed. I've used it in the past, but it's a bit too low in output for my taste. LPR35 is a completely different animal, though some may get the two confused.

Motor caps can do it in some cases. So, do you have anything to compare the Akai's to right now? It's normal for the winding to appear to slow down towards the end due to the increased diameter of the take-up reel as the tape moves to that reel.

The tape should not be touching the heads during fast-forward or rewind even if it is strung through the tape path. Check the tape lifters to make sure they engage and lift the tape away from the heads during wind. If the don't it can cause extra drag. Also check that the lifters are generally round and smooth. Worn sharp parts anywhere in the tape path can cause greater friction as well.

:)
 
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