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Telefunken Studio 1M - Cassette Deck Questions

Telefunken speed adjustment motor capstan belt pinch roller cassette

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#1 Mike

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Posted 20 July 2015 - 10:40 PM

Hello All-

 

My Telefunken Studio 1M cassette deck plays/FF/RR very slowly.  I opened her up which took some time (if anyone wants specific photos please ask) and have had a look.  Here are some questions I have...which should help me have her up and running!!

 

1.  My pinch roller may be dirty and no good (see photo).  I will try to clean first and see if that helps.  If I need to order a new one, can I just measure the dimensions and buy off Ebay?  Any other places to buy with a better selection?

 

2. I can't tell if the capstan motor has speed adjustment (see photo).  There is a small hole (~1/8" diameter, ~1/4" deep) with a plastic sheet over it.  I can drop a jeweler phillips head or allen key through this shet.  I tried different sizes and nothing seemed to "catch".  Does it even look like that is for speed adjustment (theres nothing else)? What type of bolt is typical for motor speed adjustment?  Bonus: do you know what I need for my specific model?

 

3.There are these two plastic (semi-transparent) "columns" connected to the deck.  They connect into the board behind the deck (see last few pictures).  I forgot to take a photo of this before I disassembled...which is why I'm in trouble.  They unhooked very easily (at the lower tip of this plastic).  The attached photos show (1) the plastic pieces, and (2) photos attempting to show where they connect to.  Any help here is appreciated!

 

 

FYI..I don't think its the belt.  I ordered a new belt kit and the drive belt is maybe 3-5% smaller.  I don't think the old belt was loose.

 

 

Thanks as Always!

 

Attached File  Pinch Roller.jpg   95.07K   55 downloads

 

Attached File  Motor Speed Adjust.jpg   109.4K   36 downloads

 

Attached File  Plastic Columns.jpg   101.8K   32 downloads

 

Attached File  Location of Clip.jpg   118.27K   38 downloads

 

Attached File  Zoom In.jpg   83.3K   34 downloads

 

Attached File  Zoom Out.jpg   96.04K   44 downloads

 

Attached File  From Backside of Unit.jpg   62.12K   37 downloads

 

 



#2 baddboybill

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Posted 21 July 2015 - 01:49 AM

Pinch roller is dirty but is for play mode. Ff and rew could be loose belts or bad tires ( if applicable).


Bad Boy Bill

#3 Mike

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Posted 21 July 2015 - 09:30 PM

Thanks BBB!!  That's great to know.  Since everything plays slow there is a good chance it is not just the pinch roller (or its the pinch roller and something else).  

 

I've attached some more photos.  You can see a small gear from the (back of deck) right above the plastic yellow/white piece attached to each spindle.  The gear's teeth are small but they are not chipped and have a uniform length.

 

When I removed that large piece (copperish color) which connects to the capstan motor (via the drive belt) you can see all the tires.  I don't know how you can possibly tell if the tires need replacement?  I'd assume that if the rubber is there, then it is good.  Should I wash each of them with a small amount of dish soap and water?

 

Can you see anything out of place that could potentially be the issue?  Why does everything play slow with my deck  :bang:

 

If anyone can help with any of my other issues that would be awesome.  There has to be someone that owns one!  I want this think working more then anything else at the moment.  I WANT BASS  :clap:

 

FYI...I moved this discussion into the telefunken tech area because I wasn't getting any feedback in the other forum.

 

Thanks!

-MT

 

Attached File  Front of Deck.jpg   71.1K   27 downloads

 

Attached File  Gear above spindle.jpg   112.18K   44 downloads

 

Attached File  Back of Deck.jpg   99.3K   56 downloads

 

Attached File  Back of Deck with Tires.jpg   71.27K   27 downloads

 

Attached File  Drive Belt.jpg   91.24K   25 downloads

 

 

 



#4 Mike

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Posted 21 July 2015 - 10:15 PM

I've done some research for cleaning / restoring rubber.  You are right...that shine on the pinch roller shouldn't be there.  What about any of the following:

 

1. MG Chemicals product called Rubber Renue is mainly acetone, which will remove the top layer of hard dried out rubber

 

2. S-721H Cleaning Fluid, by American Recorder which is a rejuvenator (used after the Rubber Renue)

 

3. Ive also read that formula 401 works great to clean rubber.  I'm not sure I buy this one.

 

4. I've also read that a 50/50 mix of simple green and water is great for cleaning....just make sure Q-tip is damp not drippy.

 

Any ideas for me to try?  Sorry for all the questions....but this is helpful.

 

-MT



#5 baddboybill

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Posted 21 July 2015 - 10:24 PM

If it only needs cleaning it's possible but if rubber is dried out it will just crack. Replacing is best thing. The tires are for ff /rew and is most likely slipping. You can try to clean with soap and water. If rubber is still soft you can use small amount of isopropyl alcohol with qtip and wipe dry.


Bad Boy Bill

#6 Superduper

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Posted 21 July 2015 - 10:51 PM

Mike, you keep asking about this. Frankly, anytime a deck is disassembled this far, just clean all the parts for good measure. The pinch roller is glazed and the capstan needle needs cleaning & polishing but you already know this so don't ask, just do it. If your deck is mainly running slow, without other noteworthy issues, then there's nothing really that all those photos are gonna show us. Either there is excessive friction in the transport assembly or the motor is running slow. Old grease frequently dry up and get sticky or hard. Either way if everything doesn't seem to roll without drag, either work it while applying isopropyl to dissolve the old grease or disassemble and correct. A tiny drop of synthetic oil might help to restore any lubricant lost from the IPA cleaning. As for the motor, a drop of oil should be applied to the sleeve bushing. Operate the pulley by hand (without belt) and make sure it does not drag.

To the motor, it does appear that there is a speed adjustment. A small flat jewelers screwdriver is used for adjustment but NEVER force it around. If you turn it to the stop and keep going, it will give and you WILL break it. By the way, that pot is prone to oxidation like any other control so a small tiny spritz of deoxit before adjustment should ensure it adjusts properly. Of course if the motor does not get proper voltage, it will run slow too.

As for slippage, a slipping capstan needle usually results in the tape running fast, not slow. That's because the take up reel naturally runs faster than the capstan to prevent any slack which would result in balling of excess tape and the tape getting "eaten." So naturally if the tape gets pulled past the slower running but slipping capstan and pinch roller, then you'll observe the audio being too fast. This presumes the take up reel is working properly and not slipping.

If you've addressed everything and tape speed is still slow but everything else seems normal, and you've confirmed that motor is getting proper voltage, then it's entirely possible that the motor is tired. Replace it with an adjustable one and that should solve your problem.

As you can see, some advice here requires you to be able to do typical DIY chores while possessing good mechanical aptitude and at least some basic understanding of electronics. If you really need step by step handholding, perhaps you really should pay a tech to fix this for you. Some repairs really are hands on and can't be done via a few pictures and descriptions. Hope this helps you and hope you try all the steps and advice here before dipping into the knowledge base again. Good luck.

#7 Mike

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Posted 21 July 2015 - 11:47 PM

Thanks.  I suppose I get too caught up in the fact that everyone seems to have their own technique for doing something.  I just need to get working on it....and go with the consensus (if there is one).  I'm also afraid to make an irreversible mistake...but gotta try......a good tech is hard to find where I am.  

 

These instructions were very helpful.  



#8 trippy1313

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Posted 22 July 2015 - 01:04 AM

And good techs gotta start somewhere, we got enough info and help here we can at least become decent techs. Hopefully. Haha.

#9 devol-toni

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Posted 22 July 2015 - 04:29 AM

Mike, follow the all Superduper's guides and you will do the repairing for sure.

Superduper is our tech guru here :yes: 

Good luck.



#10 Superduper

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Posted 22 July 2015 - 10:26 PM

Toni, thanks for the vote of confidence but there are no guru's here, just a bunch of diy'ers that do what we need to do to keep things working

 

Mike, it's entirely possible to mess up and cause irreversible damage.  We have all done that at one time or another and that's a fact of life and part of the learning process.  Call it the cost of tuition for learning this hobby if you want to delve into the technical side.  That's why most of us started with something cheap and easy.  You happen to start with M90's and Telefunken Studio 1's, so your tuition has the potential to be more costly than most.  However, this is simply something that you have to jump in and do.  No amount of staring and advice search or chatting is going to result in your box getting fixed.  That's what DIY'ers do....  they learn by fire.  And if you are searching for a magic bullet that is going to be the single panacea for your decks issues, you won't find it.  The problem could be a failure (motor or circuit resulting in low voltage to motor), or more likely, the case of a deck 30 years old accumulating wear and tear and degraded lubricants and oxidation.   

 

All those little idler wheels?  They should rotate freely without drag.  Even though they are thin and rides on a small needle shaft, it is still possible for them to introduce drag.  If all of them have a little bit of drag, the collective total results in enough drag to become an issue.  I have personally seen these small pulleys almost frozen on the shaft.  Removing them, polishing the shaft before reassembly makes a world of a difference.  In all those photos you show, what are we supposed to see?  If something was amiss that was visible and that we could identify, your deck would likely already have serious operational issues.  Yours is just a bit slow.  Well, we can't see slow, and we can't see drag, and we can't tell if your lubricant is dried, and we can't test your motors voltage, etc.  The boombox is in front of you, YOU are the man on the spot, and so thus, it's up to you.  Sorry, it's really hands on, and you'll learn as you go, and there is no step by step.  Anyhow, you can simply adjust the pot in the motor adjustment hole, but if there is no response, then that could be problematic suggesting maybe failed internal regulator or broken pot  Or if there is insufficient range of adjustment, then you really need to look at voltage and see if it's correct, and too much friction is a good possibility.

 

Mike, follow the all Superduper's guides and you will do the repairing for sure.

Superduper is our tech guru here :yes:

Good luck.



#11 Mike

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Posted 28 July 2015 - 10:20 PM

Thanks.  I have a lubricant and a rubber rejuvenator on the way.  Once they arrive (and I have some time) I will be playing with the deck and will report back.  I do very much appreciate the information.  Much SuperDuper said was both very useful and new to me......and I've done lots of research online.   LOTS.

 

FYI....I do have two smaller boxes.  They just don't seem to give me problems.....except belt replacement.....yet.  Also, the deck mechanisms are simpler and easier to comprehend.

 

Mike



#12 Mike

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Posted 29 July 2015 - 10:50 PM

To Summarize this is what I plan to do for general maintenance of the deck:

 

  1. Lubricate (Liquid Bearings Synthetic) the motor, idler wheels, and pinch roller.  I don't see any reason to do this for the brake and clutch.
  2. Clean all rubber tires with rejuvenator (American Recorder S-721H) and also the thick belt around the metal flywheel.
  3. If pinch roller is still dirty, I will use Rubber Renue on the pinch roller.
  4. I will clean the guides and miscellaneous plastic with the S-721H.
  5. I will clean the heads with isopropyl alcohol.
  6. Re-belt
  7. Try her out....and play with motor speed as needed.
  8. I will deoxit the switches and general cleaning with can of air and IPA before closing her up entirely.

If its a motor issue I will need to learn soldering next.  Replacement motors seem easy enough to procure.



#13 Mike

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Posted 02 August 2015 - 05:09 PM

Today I gave the boombox a thorough cleaning (skipped lubricants for now).  That Rubber Renue is amazing for getting the grime off the pinch roller.  I completely dirtied 50 cotton swabs.  Keep away from plastics.  I had a touch that hit some plastic and it started to attack the material.  American Recorder was used for the rest of the rollers and is fine with plastics.

 

When I put the deck back together, the flywheel and sprockets (spindles) appeared to be looser then I remembered.  The flywheel is fairly heavy and it just didn't seem to fit right.  I was hoping that the metal plate would hold it in place once I put it on.  Notice that the back of the metal plate has a threadless bolt that accepts that male threadless cylinder at the top of the flywheel (opposite side of capstan).  This appears to be the only support for the flywheel.  Is this normal?  The flywheel does not stay statically balanced.  It will move around when being touched.

 

Anyways, I hooked her all up (even figured out how to get those plastic pieces clipped onto the PCB).  When I turned her on, the motor initially was engaged.  When I hit play the cassette moved and I watched the tape turn....but I couldn't get any sound out of her.  The speakers made a slight hiss, so I knew they were working.  When I hit stop, the heads would raise, but the motor still spins.  Only the play button would work (FF/RR wouldn't).  FF/RR wouldn't engage.

 

I've previously read that a loose belt can be the reason for a motor to play constantly.  I feel that the loose (unbalanced is a better word) flywheel is causing the issue.

 

When I disassembled her, all buttons worked again....or at least appeared to engage when pressed.  Does anyone have any words of wisdom?  Any suggestions for how a flywheel typically "rests" on the deck (and the sprockets)?  I looked back at old photos and don't see anything different.  I do remember the flywheel being being balanced when I first took that metal plate off.  I've attached 3 photos that might help.  Thanks!

 

Attached File  Capstan inserted to threadless bolt.jpg   122.44K   46 downloads

Attached File  Back of Plate where Flywheel Rests.jpg   117.18K   32 downloads

Attached File  Flywheel fitting that is inserted to plate.jpg   99K   47 downloads



#14 devol-toni

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Posted 02 August 2015 - 07:05 PM

Mike! You need to check the micro switch that I marked with red arrow on the pic below if it's in order. It's easy to brake those switches when handled with the mecha during operation of cleaning etc.

I'm not 100% sure but i think that this switch engage the motor when you pres the play button and ff/rr . There should be another one for activating the playback head (on the back side maybe).

 

For the sound, check to see if some wire is broken like those marked with the yellow arrow and check all the connectors if it is fit on the place properly.

Good luck

 

Attached File  Graphic1.JPG   66.21K   43 downloads



#15 Ela

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Posted 06 February 2017 - 06:35 AM

Hello everybody and thank you for all the info posted. I also have a Telefunken Studio 1 stereo and the drive belt had to be replaced. At my local store there are many types of almost identical belts, but the person who tried to make the repair has lost the old belt. Now I just need the dimensions for the new belt to buy it. Can you help me, please?



#16 BoomboxLover48

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Posted 06 February 2017 - 07:17 AM

Superduper shared lots of valuable information here! wow! :bow:

 

 

For capstan bearings I used sewing machine oil. I know synthetic oil works the best. For these bearings it should be a very low viscosity oil. 

 

https://www.amazon.c.../dp/B007GOVZLG 

 

Anyone tried the synthetic oil like this?



#17 baddboybill

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Posted 06 February 2017 - 07:47 AM

Hello everybody and thank you for all the info posted. I also have a Telefunken Studio 1 stereo and the drive belt had to be replaced. At my local store there are many types of almost identical belts, but the person who tried to make the repair has lost the old belt. Now I just need the dimensions for the new belt to buy it. Can you help me, please?


My suggestion is buy a few similar sizes and test for bet fit.:-)



Also tagged with one or more of these keywords: Telefunken, speed, adjustment, motor, capstan, belt, pinch roller, cassette