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Cassette tape warbling

P

Palmat

New Member
Hi!

I recently got back into the cassette game after finding an old deck at a thrift store for next to nothing. The deck is a Sony tc188 sd and was almost in perfect condition and I have since bought a small collection of new and old cassettes. And now to my question: some cassettes has a warbled sound like the speed becomes unstable. For example I got a decent tape of Def Leppard´s Adrenalize and it started out fine but after a few songs the speed became unstable och the sound warbly. I did the whole fast forward/rewind thing a couple of times to no avail. Just the other day I came upon the same cassette but this time still sealed and still had the same issue with the warbly sound. Just for comparison I popped in the same tape in a small portable cassette player that I had laying around in storage. On that device there was no warbling or such. What could be issue be? Is it the tapes or is it the Sony tape deck? I have a bunch of new and old cassettes that play without a hitch or warble on the Sony deck so it seems to work fine, but just not with some cassettes (the Def Leppard one and a sealed copy of a Tears For Fears album). Anyone who has had the same problem?

/Mathias
 
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It could be the drive belt, if it has one.
I had the same problem with my 1972 vintage Sharp RT442H cassette player. I order a new one on-line.
Cured the problem ten years ago. Still working perfectly
 
This deck is over 40 years old, and almost definitely should have its belts replaced. This is one reason that most old tape decks aren't worth much; the amount of work required to get at the belts makes it not worth doing. On the other hand, electronics of this age were designed to be repaired, so it's probably doable if you're handy. And you're in luck, the service manual can be found here, and while it doesn't specifically have instructions for changing the belts, it does show you how to disassemble it.
 
Doghouse said:
It could be the drive belt, if it has one.
I had the same problem with my 1972 vintage Sharp RT442H cassette player. I order a new one on-line.
Cured the problem ten years ago. Still working perfectly
Click to expand...

Thank you for the input. I´ll try to see if I can get hold of replacement belts asap.
 
swechsler said:
This deck is over 40 years old, and almost definitely should have its belts replaced. This is one reason that most old tape decks aren't worth much; the amount of work required to get at the belts makes it not worth doing. On the other hand, electronics of this age were designed to be repaired, so it's probably doable if you're handy. And you're in luck, the service manual can be found here, and while it doesn't specifically have instructions for changing the belts, it does show you how to disassemble it.
Click to expand...

Thank you for the heads up regarding the manual. Hope that belt changing is not too difficult.
 
Some other things occurred to me that you should check for before you open it up:
  1. Turn the deck on but don't put it in play (most non-portable tape decks leave the capstan running the entire time they're turned on). Open (eject) the tape well and examine the capstan - make sure it's not wobbling. If it is, it's probably best to give up and get a different deck. While that's theoretically fixable, realistically it's not going to happen.
  2. Clean the capstan and pinch roller. Isopropyl alcohol on a cotton swab can be used occasionally, although if you're going to be keeping this I'd recommend looking for cleaning fluid. First clean the capstan, then put the deck in play (since your deck has mechanical piano-key controls, it should allow you to put it in play without there being a tape inside. If it doesn't, feel around the top of the well for a little lever and push it up; hopefully that will be the interlock that allows you to enable play) and clean the pinch roller while it turns. While you're in there, clean the heads, but use a different, clean swab for that
  3. Still with the deck in play, take a look at the spindles. The right (takeup) spindle should turn counterclockwise. Counterintuitively, the left (supply) spindle should turn clockwise. This is to maintain tension on the tape while it's playing. It actually has very little torque and you should be able to stop the left capstan by applying very slight pressure to it with your finger (although thinking about it after I typed this, I believe some decks just apply enough friction to the left spindle for tension, so if it doesn't turn that may not be a problem).
  4. Lastly, examine your cassettes. Make sure they're not missing the little felt pad on a piece of metal in the bottom middle opening.
Let us know how this works out.
 
I can't remember which supplier it was, but one of them said if they didn't have your particular belt in stock, they could make one for you.
Just a question of measuring the old belt and deducting a bit for the wear.
I got a new blt for my vintage Philips tuntable. In fact I got two and there's room under the turntable to store it. So I'll be able to find it if I ever need to replace it again.
 
Been a long time since I messed with cassettes ..


Clean the capstan and pinch roller for sure ..
Unrelated to the warble, but demagnetize the head and you may find improved treble response ..

Those are just basic maintenance for a cassette deck ..
Only on certain tapes ??
 
Last edited:
Above advice is good. One other possibility is that the lubricant in the tape has dried out and causing the tape to bind a bit.
 
Palmat said:
(the Def Leppard one and a sealed copy of a Tears For Fears album). Anyone who has had the same problem?
Click to expand...

You likely have the rarest versions of those albums. Probably worth a small fortune.

Back in the day, before auto-tune, producers were looking for the next latest big thing. A few experimental producers thought "warbling" was going to be huge and, against the will of the artists, released a small number of specially duplicated tapes "pre-warbled". They didn't sell well and 99.99% of them were sent to the crusher.

;)
 
swechsler said:
Some other things occurred to me that you should check for before you open it up:
  1. Turn the deck on but don't put it in play (most non-portable tape decks leave the capstan running the entire time they're turned on). Open (eject) the tape well and examine the capstan - make sure it's not wobbling. If it is, it's probably best to give up and get a different deck. While that's theoretically fixable, realistically it's not going to happen.
  2. Clean the capstan and pinch roller. Isopropyl alcohol on a cotton swab can be used occasionally, although if you're going to be keeping this I'd recommend looking for cleaning fluid. First clean the capstan, then put the deck in play (since your deck has mechanical piano-key controls, it should allow you to put it in play without there being a tape inside. If it doesn't, feel around the top of the well for a little lever and push it up; hopefully that will be the interlock that allows you to enable play) and clean the pinch roller while it turns. While you're in there, clean the heads, but use a different, clean swab for that
  3. Still with the deck in play, take a look at the spindles. The right (takeup) spindle should turn counterclockwise. Counterintuitively, the left (supply) spindle should turn clockwise. This is to maintain tension on the tape while it's playing. It actually has very little torque and you should be able to stop the left capstan by applying very slight pressure to it with your finger (although thinking about it after I typed this, I believe some decks just apply enough friction to the left spindle for tension, so if it doesn't turn that may not be a problem).
  4. Lastly, examine your cassettes. Make sure they're not missing the little felt pad on a piece of metal in the bottom middle opening.
Let us know how this works out.
Click to expand...

Checked the capstan and it is not wobbling. Cleaned capstan and pinch roller. Cassettes all have the felt pads. The problem with some cassettes persists. Have ordered a new pinch roller and belts. Hoping this will fix it. Will post again when I have changed these parts and playtested.
 
restorer-john said:
You likely have the rarest versions of those albums. Probably worth a small fortune.

Back in the day, before auto-tune, producers were looking for the next latest big thing. A few experimental producers thought "warbling" was going to be huge and, against the will of the artists, released a small number of specially duplicated tapes "pre-warbled". They didn't sell well and 99.99% of them were sent to the crusher.

;)
Click to expand...

Yeah. Deep into the warbled auto-tune scene for sure.
 
H
Akustic said:
Been a long time since I messed with cassettes ..


Clean the capstan and pinch roller for sure ..
Unrelated to the warble, but demagnetize the head and you may find improved treble response ..

Those are just basic maintenance for a cassette deck ..
Only on certain tapes ??
Click to expand...

Haven't tried the demagnetizing thing. How does one do that? Yeah, only some cassettes warble. I´ve got about 20 cassettes as of now (both newly produced and some vintage tapes). All of them have a stable sound stage without warbling but the Tears for Fears and Def Leppard tapes all start out fine and then starts to warble badly after about two or three songs. Also have a Bryan Adams tape that started to warble towards the end of one side.
 
So now I have changed the belts on the deck but some tapes still warble. I tried to change the pinch roller but was unable to do so.
 
Maybe a problem with the cassette that makes it bind up or drag a bit sometimes? One thing we used to do, if the cassette case was cracked or whatever, and if it was the kind with screws holding it together, was to find another one and swap the tape reel into a new case. Sometimes that fixed issues.

Unless it is something in the deck that responds to a certain characteristic of this particular tape, it has to be the tape. I thought maybe the drive belt was just loose enough that it would slip a bit if the tape reel dragged, but if you put on a new belt, that's out, right guys?
 
Can you find any commonality between the tapes that warble and the tapes that sound fine? Age or length, maybe? Do you have any non-prerecorded cassettes? Do they consistently sound good or bad?
 
If the problem is only with certain tapes, it is likely the cassette itself ...
Some of my favorite homemade tapes developed similar problems .. I was hosed ..
Luckily it was only a few tapes ..
 
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