Teac X1000R tape droop across heads

[oldvinyldude]

I have a common issue on this deck-drooping\falling away of the tape across the heads.

I have another 1000R that is working correctly, and I am able to use it for comparison.

Attempts to resolve have not been successful:

Changed belt-I have tried 2 new belts, one from Teac, and another from a source suggested here by AK member Tapetech (forget the name of the vendor), which is 16.8" and thinner than the Teac supplied belt.

I have experimented with adding and removing washers under the motor mounting plate. They have been installed under the mounting flange on the left most screw-as viewed from the motor side of the assembly. When I placed too many\too thick a washer, the belt will rub against the flywheels. I have removed a washer, and the belt does not rub, but in each case, what I observe about the belt-it does not move back and forth as much when switched between forward and reverse play, compared to my working unit.

I have swapped the pinch rollers from the working deck, paying close attention to left side\right side and front\back side for them. When they are installed on the malfunctioning deck, I have the exact same symptoms, so I believe I can rule out the pinch rollers.

Of course, if I put a significant drag on the 'source' reel-in either direction of play, I can make the loop disappear, and I know not to go dialing up the back tension to 'solve' the issue. I have to apply a lot of drag to make the loop go away, so even if the back tension is a bit low, getting it to spec would not make the loop go away.

I thought about swapping the flywheels-and this got me wondering if they are different, or are they the same dimensions?

I am also questioning whether the smaller belt movement on the flywheels than reference (working deck), is part of my problem. How do I increase this movement?

Changing washers has only changed where the belt rides on the flywheels overall, and not it's net movement when changing tape travel direction.

I have gotten very good at swapping belts, and removing and replacing the motor assembly-but no resolution to the droop......

 

[Numone]

Are the pinch rollers hitting the capstan at the same time? If there’s a delay on either side, caused by hardened grease on either of the arms, that could cause a loop. I had that issue on our X10R when I first got it. Dismantled, cleaned, greased with Lubriplate, problem gone.

 

[oldvinyldude]

No issues with pinch rollers, their lubrication, or on the engagement with the capstans. The pinch roller engagement\disengagement is immediate. Everything in the path is also squeaky clean.

I am looking at the flywheels-I have confirmation that they are different-I hope to get home and conclude that they are indeed reversed as currently installed.

I will update when I have the time to swap them, if they are incorrectly installed.

 

[Grbluen]

"Of course, if I put a significant drag on the 'source' reel-in either direction of play, I can make the loop disappear, and I know not to go dialing up the back tension to 'solve' the issue. I have to apply a lot of drag to make the loop go away, so even if the back tension is a bit low, getting it to spec would not make the loop go away."

I tried to buy an X1000R that had the same issue. I did the same trick to make the loop go away! The seller insisted on the original price despite the issue.
I left it. I'll be watching to see if you solve the problem. I bet it's something simple!

 

[mcgjohn]

Sounds like the two capstans were swapped if removed during a belt change. This would cause that problem since one is actually slightly smaller than the other. .

 

[oldvinyldude]

Update:

I found that indeed, the flywheels were swapped. I reversed them to their correct positions, but sadly, the droop continues to occur.

I adjusted the back tension (via R120) per the service manual to 50g. The manual only shows an adjustment for the right side play tension-it was around 80g before adjustment. The left side measures 40g, but I do not see any note of adjustment for the left side in play mode- only the winding tension. Measurements were done with 7" reels, wound to approximately equal amounts of tape on both reels. Readings made at 3 3/4 speed.

The installed belt is the same one as installed on my working\reference machine. The belt now moves to a greater degree on the flywheels when play direction is changed, and rides centered on the ridges-seems to be spot on, in that regard. Also, the belt rides on the motor pulley in the same pattern as the reference machine (movement along the pulley profile when play direction is changed). I don't think there is any issue there.

I have 2 other belts I can experiment with. One is thicker, the other is thinner and 17". I will try these and report back.

I can also experiment with the washer under the motor mounting plate, but since the belt seems to be riding centered on the ridges properly, I am doubting that will improve things. I predict that it will only serve to change the belt position on the ridges of the flywheels, which again, from my observations, is spot on.

 

[oldvinyldude]

In additional reading here and Tapeheads, I learned to take a look at the pinch roller stroke adjustment, pivots, and pivot stopper pads (for .5 to 1 mm clearance)

I am still working through the adjustment of the stroke, but the crude adjustment of the stroke has made the loop go away! I still need to locate the pads, so I can measure, and remove and clean the pinch rollers and their pivots, and relube. I also need to confirm that the solenoid bottoms out fully-with no sign of impeded movement.

I am hopeful that after all the above cleaning and setting of the clearance between the pivot and the stopper pads, using the adjuster nuts accessible from the top of the deck frame, that the loop issue will be solved. Stay tuned-for now, I have no loop, but I have not done a complete job yet.

I also learned from an experienced member, that I can use the adjuster pots for the FFD and REW settings, to set the back tension for play mode of the left side. This is how he adjusts play mode back tension, with these adjusters, but the deck is in play mode. I can then bring up the tension a bit on the left side from 40 to 50 g, as it should be. I am finally using the Tentlelometer that I bought 5 years ago!

It's also comforting to see that my working\reference deck has pretty close back tension set-I learned that the tension arms, when correct back tension is set, will rest slightly below horizontal. This is what I observe. I will swap out the working unit for the repaired unit, so I can test it further, etc. Then I can confirm\adjust back tension for the reference unit as well, with what I have learned here.

Thanks so much to the AK community for providing me with so much knowledge.

 

[oldvinyldude]

Sounds like the two capstans were swapped if removed during a belt change. This would cause that problem since one is actually slightly smaller than the other. .

What I learned is that the flywheels are the same dimensions-but they do differ. The difference being a ridge that the belt rides onto, when the play direction changes.

 

[Numone]

The flywheels are different diameters, which creates back tension across the heads. As you said the F&R direction change is working, I thought the flywheels were in their correct position. So, there is either an issue with delivery or the take-up capstan. I suggest you stop messing around with the deck - adding components which were not in the original specification, nor in the service manuals or updates is not a wise decision - and get it to a respected tech who has experience working on the X Series of decks. BTW, the ridge is there to carry the belt over when you engage a change of direction.

 

[oldvinyldude]

I have removed the tension arms, fully disassembled, and cleaned and re lubed, then set the stroke gap as specified in the SM. I have successfully set the back tension for all modes, and the deck is working well. Next step is electrical alignment-setting of playback level and adjusting meters. I have a signal generator now, and I have a scope on it's way to me. I know I will need to get an MRL tape to do the job fully, especially for setting BIAS for my specific chosen tape. I can proceed slowly, and likely I will have additional questions, so I will not be in a hurry, and quite possibly I will get stuck. Only time will tell.
I did measure the flywheels-they are the same diameter, nominally. The ridges obviously change the effective diameter when the belt is riding on it. The ridges are on different places on each flywheel, and the belt rides up on the ridge on one flywheel, whle riding on the other flywheel in an area without a ridge, and when the tape directions is changed, it rolls off that ridge, and rides up onto the ridge of the other flywheel-this creates the speed change necessary to create tension across the heads in each direction of tape travel. The washer under the motor mounting plate creates the condition of movement of the belt back and forth on the flywheels, while the ridges create the speed difference.

 

[MTalley]

I love threads like this that have detailed "here's what I did" responses from the OP. So far, knock on wood, my 1000R has performed pretty flawlessly after initial belt replacement, cleaning and lube. I even bought a Tentelometer and found that everything was in spec after reviving this unit. The previous owner had stored this unit away years ago after a move and subsequently ended up in long-term care after having a stroke.

 

[titanstats]

No expert on this machine, but sure does sound like improper tension somewhere. Nice deck, might be time to take it in at this point.

 

[lbcgav]

No expert on this machine, but sure does sound like improper tension somewhere. Nice deck, might be time to take it in at this point.

Sounds like the OP has everything handled. Heck, I think he's probably got a better understanding of this deck than most "techs" do. He's even got a Tentelometer for goodness sake.

 

[titanstats]

Sounds like the OP has everything handled. Heck, I think he's probably got a better understanding of this deck than most "techs" do. He's even got a Tentelometer for goodness sake.

Maybe, but sometimes it's good to have another pair of eyes look at a problem though.

 

[oldvinyldude]

For the purposes of this thread-to resolve the tape droop, I consider this complete.
Many thanks for the help here and on Tapeheads. I read so many threads here and there, and summarized my findings and items cleaned and adjusted in post #10, after first swapping the flywheels so that the ridges, which are on different places on each flywheel, are in their proper places, (a local tech had swapped them-as has been said-it's hard find a truly competent tech locally).

I will likely start a new thread for the next steps of setting playback level, meter level, and head azimuth, and then onto setting Bias for my tape stock.

 

[titanstats]

For the purposes of this thread-to resolve the tape droop, I consider this complete.
Many thanks for the help here and on Tapeheads. I read so many threads here and there, and summarized my findings and items cleaned and adjusted in post #10, after first swapping the flywheels so that the ridges, which are on different places on each flywheel, are in their proper places, (a local tech had swapped them-as has been said-it's hard find a truly competent tech locally).

I will likely start a new thread for the next steps of setting playback level, meter level, and head azimuth, and then onto setting Bias for my tape stock.

Good thread - so in the end someone actually just put the flywheels in the wrong places? Glad you found the problem, tough to track stuff like that down. I dread going into equipment where someone has done work but the job isn’t finished yet. Cheers.

 

[dr*audio]

When you replaced the capstan belt (s) did you clean the flywheels and motor pulley? If they are not meticulously cleaned with alcohol until nothing comes off, it can cause all kinds of weird phenomena.

 

[oldvinyldude]

Yes, flywheels were clean, as was the motor pulley. Belt was replaced as the old one was stretched. No goo anywhere.

I had taken the deck to a local guy, who, apparently, had swapped the flywheels.

I am glad that I have now acquired the skills to solve the issue.

 

[dr*audio]

Just a note; it's not enough for the flywheels to appear clean, you must attempt to clean them with alcohol and verify that nothing comes off. This is critical with all dual capstan machines.