Otari MX 5050 Mk. I

[neilslade]

Just bought an Otari MX 5050 Mk. I for $50 knowing it was wobbly.  All the controls and electronics are in order.

It's somewhat slow on playback, fast forward really doesn't go, rewind stops once you get enough tape on the reel- etc.

It appears to be worn reel motors. Tons of dust inside.

Now what?  Can't find motor replacements anywhere that I've seen.

I took out the right motor and used some penetrating oil on the motor axle, and that helped a smidgen to get a little more speed going.

I have a half dozen tapes recorded on the same type of machine 30 years ago and would like to transfer to my Cubase DAW. I even have
a DBX unit (which we used back then). 

Suggestions welcome.

Neil
[email protected]
www.NeilSlade.com

[ironbut]

Hi Neil,
Welcome to the forum.
It sounds like that machine may have some major problems.
When you say that it's wobbly, do you mean "machine/tabletop shaking" wobbly or are the spindles just a little off center when they're turning?
If it's wobbling badly, it probably means that it was dropped while poorly packed. The chassis could be bent and that kinda makes it a write off.

The motor issue could be from it's sitting for a long time without being used. I suggest you try running the machine without any reels attached. The way you do that is by putting some adhesive tape on the machine to hold the tensioner(s) so the machine 'thinks' that there's a tape threaded. Go through the different controls and see if running the machine this way loosens the bearings.
You should download a copy of the service/owners manual too.
http://www.tapeproject.com/smf/index.php/topic,1545.0.html

Some common issues with playback on these machines is also located here;

http://www.tapeproject.com/smf/index.php/topic,1591.0.html

The link in reply #2 is what I'm referring to.

Overall, if you get the machine working, it's a heck of a bargain. If not, you got a great deal on a parts machine and you'd be better off not spending too much time trying to get it working. Just find one that is.

[neilslade]

Mine is the 8 track, Mk. I  not a two track.

No, I meant a bit of speed inconsistency-  however, the more I played tape, the better it got-
I am suspecting  cleaning the pinch roller helped- but unfortunately, the tape (Ampex 456) is REALLY sticky.
It's

The tension on the pinch roller is fine however.

I clean the pinch roller, run a little tape, and it immediately gets gunky particles on it from the tape- the tape is nearly 30 years old,
tapes I made in 1982-1989.  I noticed that the tape "sticks" to itself once you get into the reel a bit, like it's self magnetic.  I don't know how I will deal with this.  The pinch roller immediately gets gunked up once I roll tape- I cleaned the path, and just looked again, and it's quite dirty after just rolling tape for a short while. Tape head lubricant?

I cleaned the whole tape path- it was a mess when I first got it.. I used to work part time at Free Reelin' Studio in Denver for about 10 years, and we were meticulous about cleaning the decks before and after each use. It amazes me to see such a nice deck in such neglected condition.

But beyond that, as I stated, FF doesn't function, and rewind is only good for a bit-- my tapes are stored tails out, so I don't get much past 10% of the tape when the left reel just stops. 


I'll try running the deck as you suggest-  the seller claimed it worked perfectly a year and a half ago, then it just sat.  I hope this will help.  Both motors do work, so I've been puzzled.  I don't know motor mechanics, and I am not sure what would cause "weakening" of the motors. I would think that the only thing that would affect a motor from working would be worn bearings, but that shouldn't weaken them- and if the bushings are shot, the motor wouldn't work at all.

I'll run it for a while and see.
Thanks so much-- if I can get it to work- heck, it will have been a steal. but something told me, it was a good $50 gamble.

Per the manuals- these are for the MK. II--  I don't see a Mk. I manual. Incidentally, my friend has a Mk II in good condition. And as I said, I used this same type deck for years. For all I know, this may be the very same deck-- it was bought by the seller from a local music shop here used, and may have been where the studio's deck eventually landed.

[neilslade]

Okay THIS IS CURIOUS

I decided to try and rewind and fast forward with the tape removed from the heads- i.e. I simply bypassed the heads and capstan- see photo

http://www.neilslade.com/temporary/tapedeck.jpg


WELL-  I can fast forward and rewind this way.

This seems to indicate to me that the tape itself is binding in the tape path some way and slowing things down.

Maybe I need to try the deck with a new reel of tape.

Where's the best deal on tape, if this sounds right?

[ironbut]

Your tape has what's called "sticky shed syndrome". It will stop almost any machine dead in it's tracks. It's a type of binder breakdown and Ampex/Quantagy 456 is the worst offender but it's common with many tapes from the mid 70's on. There's more on sticky shed in the "Beginner's Guide" located above the General Forum in a sticky (no pun intended).
What's important for you to know is that all those old stock tapes that you see for sale have a good chance of having this problem and unless the seller is lying and has played the tape, he wouldn't even know. This problem becomes worse with time and temp/humidity so even if it isn't bad now, the chances are good that it will be down the road.
As you now know, cleaning up the sticky mess is anything but easy but you can be sure that every time you play one of those tapes, you can look forward to cleaning the entire tape path again.
Hopefully you don't have anything important on those reels of 456. If you do need to save what's on them, baking them and transferring the sound to another machine is the way to go.

Luckily, there are new tapes that don't have this problem (it was discovered that the use of binders with certain molecular structures are to blame for this). The current manufacturers of tape are RMGI in Europe and ATR Magnetics here in the US. The Tape Project uses RMGI for their tape releases and it's a very good sounding formula IMHO. The ATR tape is a higher output tape and if you have any plans on doing live recording, you'd do well to use this tape and have your machine biased for the same.

You can buy either from US Recording Media along with lots of other supplies you might need on your tape journey.
BTW It's still useful to have the 2 track manual since most of the circuits are the same and finding a copy of the multi track manuals could take a while.

[neilslade]

I"ve been running the deck with the reels off and appear to be making some progress-  I can get the FF to work a bit, and I'm able to rewind a little more than half a reel of tape before it gives up. If I dis-engage the tension arm on the left, this helps as well, and seems to indicate that the left motor is sluggish and lacking in the necessary umph to move a fully loaded reel.

The speed in play appears better as well.

My strategy is to run various rewind/play/ff for a couple of hours, let it cool off completely for a few then repeat for however long it takes until I can ff and rewind an entire reel with it threaded.  I would imagine this shouldn't damage the machine. (?)

I did put on a newer tape that I had from the mid 90's, and the machine exhibits pretty much the same motor issues, so I don't think the sticky tape is really the only culprit here, although a contributing factor.

[neilslade]

Looks like, if we go by price, the ATR tape is the way to go for new stuff. $89-$98 for a 10.5" reel.

[ironbut]

You should check to be sure that your brakes are disengaging properly. If they're dragging that could be the problem. I've even seen mildew build up on the cotton surfaces but if your machines guts were as dusty as you described, that could be the problem. They could also just need adjustment.
If the brakes seem to be ok, it could be the tensioner that's gummed up. See the second link I provided in my first post. It may be that the tensioner isn't moving all the way so any momentary slack in the tape shuts the machine off. (btw, please describe what happens when the reels stop in more detail,.. do they slow gradually or stop all the sudden? Is there any noise before, or during it's slowdown and/or stop? Do you hear the machine shut itself off before the reels slow or after they stop?)
Past that, you may need to adjust the tape tension. Do this only once you're sure that it isn't any of the other things I've mentioned. If you don't have a tensiometer you'll have a tough time getting it back to the tension it should be set at. Proper tape tension is a huge part of what makes a machine sound good and handle tape gently.

BTW, if the newer tape you used is still Ampex/Quantegy, it could be just as bad as the other one you tried (or worse). If you get any tape squealing, that's a sticky tape and it isn't worth trying to fix the machine till you get a tape on it that doesn't squeal.

For testing purposes, there's no reason to spend the extra money on a 10.5" reel of tape. Just buy the cheapest one on a 7" reel. (oops, just remembered you have an 8 track so you probably can't buy anything but 10.5" )
Speaking of which, does your machine have a "large/small" reel switch? If so, make sure it's set correctly.

[King Arthur]

Thats a good looking deck. I hope you get it working correctly...

[neilslade]

Looks like I've got it going good-

Got FF and RW to do a whole tape--

2 problems,

1) the right tension arm WAS gummed up, so at the point where it lost tension, the machine immediately shut off.  I sprayed with teflon and its free now. Also put some on the left arm, although this wasn't so bad.

2) All my tapes are sticky. So, they'll have to be baked before I can transfer to my computer. They are shedding pretty bad;

None the less, A newer one out of the batch seems to play back now at the correct speed.  Previous the small reel position worked better than the large reel- odd, but that's how it is. I would assume large reel would have more leverage, but apparently not.

However, rewind with a full reel of tape (say 5% left on the right reel) is still quite slow- but I imagine part is due to sticky tape. I'll remove the left reel motor, clean the brake and spray some teflon penetrating oil on the axle as I did for improvement on the take up reel.  I'll get a brand new reel of tape and see how it goes.

Yea.

If that's all it is, I think this was a found treasure for all of $50-  and I can transfer all of my old material.

You can listen to the mix-downs of much of this here:

http://www.neilslade.com/audio/info.html

and history of my recordings here: http://www.neilslade.com/music/BMCentral.html

The next step will be baking all of these tapes...

Thanks everyone.

[ironbut]

Hey hey! Good deal!

Sometimes if you're lucky, it's like that minty car you find for sale that doesn't run but you notice that the coil is cracked. Just don't make the original owner 'pay you' to get it out of his driveway,.. very bad karma!

These machines can be somewhat like a car since so many of the problems involve mechanical rather than electronic solutions. After all, if you found a Porsche Speedster in a barn with only 10k miles you wouldn't expect it to start right up and run very well.
And just like that old bathtub sports car, you can expect that as you free one sticky mechanism up, another one will rear it's ugly head. But once you get a machine up and running pretty well, things will improve a little just by playing it. That doesn't mean you're off the hook on cleaning and lubricating that mechanism since it won't take much for it to revert back to it's sluggish ways.

[neilslade]

Ack.

Further experimentation shows same problems.  It appears as though some tape is LIGHTER than others and places less strain on the reel motors.

I've tried various reels, and even a fairly new reel from 1994, and it won't rewind all the way, as others-- the motors just don't have enough UMPH to get through past the half way mark when threaded through the tape path. This is after cleaning both again and using penetrating oil on the spindle axles. The tape path is clean, so, the tape isn't binding.

So, my guess at this point is NOT for mechanical root of problems- but rather than the power supply is giving up and not supplying
sufficient current to the motors for them to run at full capacity under load.  This could be the transformer/power supply or some other
electronic component responsible for regulating voltage. Such a thing is far beyond me to troubleshoot, and my guess is that
a power supply would be impossible to replace for this thing, and not worth the time or expense to diagnose and fix--  could buy
a used Otari for less money.

At this point, I've spent hours on this machine, and I'm sick of messing with it. It was worth a shot- and actually listening to my
original tapes right on the machine (and I can get some to play) makes me realize how far down the road the mixdowns were
from the original recordings.

One solution that may work would be to transfer one track/song at a time to an empty reel, and then work with that. This would
present minimal physical load to the motors, and I probably might be able to get it to work in this manner, as it appears physical load
is the major hurdle for this machine.

But I need to bake the tapes first anyway.

[Tim]

Make sure you deck is 120Volt power input (not 220)

If 120 volt, there may be nothing wrong with your deck. It all may be defective tape related.  You could have defect (sticky) tapes and a gummed up tape path (residue from the defect tapes).

Put the deck upside down and carefully remove every speck of tape residue from the guides. Use a strong light and a magnifier. Often you need to use acetone or MEK.  To clean residue in the corners of the tape guides sometimes a push pin/safety pin point is needed to get every speck out. Don't scratch the guide surface!  A very small amount of tape goo in the guides can jam the tape and cause tape speed problems (both in play and fast wind).

Next, test the motors:  Tape the tension arm in the up position so that the deck will work without tape.  Hit FF.  The right hub should spin CCW and should be quite strong in torque and will be difficult to stop by grabbing it.  The left hub should spin CW with a weak torque.  It will be very easy to stop by hand.

Hit rewind.  Left motor will spin CW with very high torque and right will spin CCW with very weak torque.

Next, put on a new blank tape.  Check FF and rewind speeds.  Record some music and play back and see if the music pitch is steady/unwavering.

If your new tape functions fine, then all of your old tapes are defective and should not be used unless properly baked (dehydrated).
 

[neilslade]

1) FF--  fairly easy to stop the right motor by grabbing the hub. I compare with the left hub, not a GREAT deal of difference.

2)RW-- fairly easy to stop the left motor by grabbing the hub.  Compared with right, not a GREAT deal of difference.

Guess that wraps it up.

As I originally suspected, these motors are not performing as they should.  Some electronic something at work here I suspect.
I cleaned the tape path pretty good previous. We did this at the studio before and after each session so I know what to look for.

A TSR-8 for sale locally in good condition may do the trick. Not an Otari, but it's got DBX (I need that for my old tapes). IT should
serve to at least transfer my music.  Here's a question, if I pick up a Tascam MSR-16, can I use it to play my 8 track tapes, each 8 track tape spread over two of the MSR-18 tracks?  Would that work?

[Tim]

Why not have an experienced repair technician look at it (someone with RTR expertise)?  Might be a simple fix (if the deck is, in fact, broken).