OK, cassette tape gurus. We're stuck.

EddyR and I have a couple of vintage silver-faced Sony cassette decks. His is a TCK-5, and mine is a TCK-60. They have the same condition, though they have different drive mechanisms. Even after replacing the main drive belts on both machines, there is a slight "warble/waver" to the sound on playback of both decks.

You can hear it best on a held note on a violin or voice -- we're speculating it must be in the background continuously, and then we'll periodically hear a slight distortion (waver -- sort of sounds like the tape barely dragging). It happens no matter the quality of the cassette being played.

EddyR has experimented with different drive belt widths and tensions on both decks, and this does not have any affect on this wavering sound output -- unless he goes way out of range with a very loose belt. So, we're befuddled. Is there something inherent to Sony's design at this time that causes this? It occurs when the decks are stone cold, or warmed up.

We're open to any suggestions. Both decks are in fantastic original cosmetic condition -- mine's LCD meters even work -- so we'd like to get them sonically equivalent.

Thanks!

OK, cassette tape gurus. We're stuck.

EddyR and I have a couple of vintage silver-faced Sony cassette decks. His is a TCK-5, and mine is a TCK-60. They have the same condition, though they have different drive mechanisms. Even after replacing the main drive belts on both machines, there is a slight "warble/waver" to the sound on playback of both decks.

You can hear it best on a held note on a violin or voice -- we're speculating it must be in the background continuously, and then we'll periodically hear a slight distortion (waver -- sort of sounds like the tape barely dragging). It happens no matter the quality of the cassette being played.

EddyR has experimented with different drive belt widths and tensions on both decks, and this does not have any affect on this wavering sound output -- unless he goes way out of range with a very loose belt. So, we're befuddled. Is there something inherent to Sony's design at this time that causes this? It occurs when the decks are stone cold, or warmed up.

We're open to any suggestions. Both decks are in fantastic original cosmetic condition -- mine's LCD meters even work -- so we'd like to get them sonically equivalent.

Thanks!

Well I'm certainly not a cassette expert by a long shot, but have had a dozen or more thrift store specials through here over the last 5 years or so. They all have or developed problems sooner or later and I would just move on to the next one :thmbsp: Actually I'm quite happy with my new Pioneer CT-F950 I found recently and cleaned it up, put new belts and demagnetized it and it is really singing for me. However I know in time it too will fail me like so many ex-girlfriends in my past. :) Such is the way in life with women and things mechanical!

Anyway, one thing to keep in mind is that the last tape speed drive components are the capstan shaft(s) and pinch-roller wheels. This is what actually contacts the tape and moves it across the tape heads. Pinch-roller rubber can get hard with age, change it's grip and even develop flat spots. So while new drive belts and cleaned up capstan motor can help an old aging deck, there is still the above mentioned parts to consider.

Looking forward to hearing from real cassette experts on this subject, as I still find the machines and the media fascinating :thmbsp:

Lefty

This is called "flutter" and it comes with the territory, especially on the slow speed (1-7/8 ips) cassette transports. If the period of the speed fluctuation is longer, it's called wow (wooooowwwwwwwwowowwowwwoowowowowwww). It might be exacerbated by bad rubber parts. Sometimes, improvements may be had without replacement. Clean all rubber parts (including the rubber idler that drives the tape against the capstan) and their pulleys with isopropanol and treat (at least) the belts with antislip compound/rubber rejuvenator. Be sure to clean the capstan with isopropanol as well. Couldn't hoit.

Isopropanol dries out rubber and should not be used on rubber parts. Trust me, I found out the hard way by killing the pinchrollers on my Denon DR-M44 when they were 3 years old. Use Ethanol, vodka works fine. Other possible culprits are, the motor, and the capstan bearing. If the pinchroller is at fault, usually on old decks like this rejuvenation doesn't work. Replacement is the only option.

A lot of cassette decks (including most of the older Sonys I believe) also have a clutch between the drive motor and capstan(s). The clutch could be slipping and may just need to be cleaned and have the tension adjusted (one of my TC-209 decks had a very loose clutch when I got it and it would just stall out and stop periodically).

A lot of cassette decks (including most of the older Sonys I believe) also have a clutch between the drive motor and capstan(s). The clutch could be slipping and may just need to be cleaned and have the tension adjusted (one of my TC-209 decks had a very loose clutch when I got it and it would just stall out and stop periodically).

I forgot about clutches; there is often a clutch for the take up reel, the clutch could be grabbing, which causes flutter. You take it apart, clean the felt and the plastic with isopropanol (ok for this purpose) let dry and re-assemble the clutch.

I really appreciate this site and the members. I have learned so much here. I just cleaned up my Yamaha deck that I bought back in Dec. the A side sounded muffled after cleaning it was perfect. I had a Technics deck back in the late 70's and it seems like I had a lighted wand of some kind for demag. any body ever seen one and are they any good?

Seems like I remember something about the TAPE itself contributing to the problem;many playings & it gets stretched. Also, rewinding/fast-forwarding doesn't help. A lot of the prerecorded tapes back then were made on tape that was so crummy, it wouldn't have passed muster for dictation duty.-Sandy G.

Thanks for the suggestions people.

We've eliminated it being a tape problem -- we can play a tape that warbles (flutters) on the Sonys on another deck (we have about 8 to choose from) and it sounds fine. Also, new tapes, old ones, home-recorded (Maxell UDXLII) ones -- all flutter on the Sonys, but OK on other decks.

Looks like the clutch may be our next investigation. Any one have service manuals for these decks?

Thanks again for your advice.

No manual, but here's how to check the clutch:
Put it in play with the door open. Grab the take-up reel, using only a little pressure, not enough to stop it. Apply gradually increasing pressure until it stops turning. The mechanism will try to continue running for a bit before the autostop shuts it down. If you feel a vibration in the take up reel, or any grabbing or uneven torque, the clutch needs to be rebuilt. It is really a straight forward take - apart, reassemble job, no manual needed. Take the mechanism out so you can get to the reel assembly. The little cap on the reel spindle pulls off (carefully). Then there will be a clip or plastic washer that hold the reel assembly on the shaft. Remove that without it flying across the room. Then the reel assembly comes off. Then you can take it apart.

First thing I checked was the pinch roller and the fast forward and the tension clutch.I have repaired a lot of decks.I repaired movie cameras for many years and they use the same type of clutch.There must be something common to this series of Sony decks.We are hoping some one has seen this problem on this series of decks and will recognize the problem.The transport in these two decks is very similar but the motors are nothing alike.
EddyR

There has to be someone with some new idea's. Did I scare you all away?
Ed

Is there also some kind of clutch assembly used to give back tension to the tape? This would be on the supply reel spindle. If the spindle was actually alternately sticking and jerking counterclockwise (under the pull of the tape) this would have the tape moving past the heads in a similar jerking motion. Result: flutter. Worth a look-into, I think.

Other details I'd like to know: is the flutter constant regardless of the length of tape used? Is it worse at the beginning, middle, or end of a tape?

Only 2 things left I can think of:
1. The capstan bearing (the sound of Taps is heard softly...)
2. The motor. Try gently tapping the motor with the handle of a screwdriver. If the warbling gets worse (not while tapping it but afterwards) the motor is toast. You can probably buy a Mabuchi cassette motor from www.mcmelectronics.com to replace it. You need to know the direction of rotation as seen from the front, and the voltage. The motors have several screw holes on the front for different mounting patterns. You should be able to adapt it if you are dedicated to saving the deck.

Ok, this is going to read like a shameless plug so first a disclaimer -- I have no financial interest in NakDoc's shop, but I do have an interest in spreading word about his capabilities to AK members based on my experience with his troubleshooting/repair skills.

As you can see from the posts in this thread, EddyR and I had run out of repair options on our Sony decks. EddyR is no lightweight audio repair guy either -- he's forgotten more than I'll ever know about audio, and I've been taking consumer electronic gear apart (and even getting it back together) since the late-'60s. I've also worked with military electronic techs in test and calibration labs, and seen some real electronic wizards at work.

Seeing how I was driving through Nashville, TN on business, I hauled my fluttering Sony TC-K60 deck to NakDoc at his HiTech Service store there for his expert evaluation/repair of this frustrating deck. Even though his cassette specialty is NAK decks he didn't bat an eye at the Sony.

Within a few minutes he had isolated the problem to being mechanical (not electrical) something was dragging on one of the transport wheels. With factory service manual in hand, he determined that a nylon rivet had lost its head and was allowing a metal plate to rub up against the non-driven playback reel -- thereby creating the drag that was causing the tape flutter on playback. A subtle problem.

After disassembly of the transport, he found the rivet's head inside the deck and reattached it. A quick tune-up, and this old cassette horse sounds great. The cool LCD meters are a' jumpin'.

So, thanks to NakDoc for his superior troubleshooting skills and patience to explain to me what was wrong. He really embodies the spirit of AK.