Otari MTR90 record head 10k tone fluctuates back and forth.

[arthurdb]

As someone else said, the tape tension seems to be too low. Did you double check the tension setting? Do you have a tentelometer?

Since the fluttering seems to be linked to the rotation of the supply reel, this might not be the only issue:

The bottom flange wobbles a bit. When it comes to two-inch tape I only have deep experience with the JH24, but on those decks, the bottom flange is a crucial part of the transport, and needs to be extremely stable and at the perfect height.

You've mentioned using several new reels, are these from the same batch/source? They could have been a manufacturing defect, or maybe they have been stored improperly for too long by the dealer... Since you have a brand new MRL tape, how does the unwinding from the supply reel look like with the calibration tape?

 

[RoadrunnerOZ]

The lock of the reel tables to the motor shafts is via two Allen grub screws for setting reel table height which must grip to the two flats on the shaft that are at 90° to each other - if these are mis-located or not fully tightened there will be an eccentric action and wobble to the reel as the screws take up and let go.

 

[RoadrunnerOZ]

You've mentioned using several new reels, are these from the same batch/source? They could have been a manufacturing defect, or maybe they have been stored improperly for too long by the dealer... Since you have a brand new MRL tape, how does the unwinding from the supply reel look like with the calibration tape?

The original problem appears on record/repro - using the MRL playback alignment was fine with no fluctuations:

mark II. Brand new MRL is fine everything looks good there when doing repro alignment no fluctuations.

It would seem that slight fluctuations on record then of course again on repro are compounding the error. The test tape is not showing these on repro probably due to the spread of the pre-recorded signal across the tape where slight vertical motion of the tape would not affect the output.

 

[arthurdb]

Yes, obviously the full track MRL is going to play back much better when the tape is fluctuating up and down. I was wondering specifically how it unwinds compared to the tape on the last video where the tape doesn't seem to unwind very well. It's probably lack of tension but it could also be a defect of the tape. I know MZFI said he tested several new tapes, but unless they are from different sources, it doesn't completely rule out tape defects.

 

[RoadrunnerOZ]

Are these tapes working fine on another machine?
If tape is stored tail out then you have to do a full rewind before commencing use anyway which would preclude stop/start bad packing of tape on the reel. Any tape stored head out needs to be wound fully forward and then rewound before use. Any new tape should be wound fully through the whole reel before use. Looking at the packed tape through the spoke gaps on the reel after a wind through you can see if it’s packing properly on wind.