Cassette recorders that chew up tapes

[liamoliver]

What causes tape recorders to chew tapes up, and more importantly, how do I prevent it from happening again?

Also, what is the best way to make a chewed tape flat again?

[paulsherwin]

There was a thread about this a few weeks ago: https://www.vintage-radio.net/forum/...ad.php?t=15662

Paul

[Steve_P]

The straightening out of chewed tapes is a problem that has not been dealt with.

The simple way is to chop out the chewed bit and re-splice.

Sometimes this is the only way. If it's only partially chewed, then get a heavy book, put the chewed bit of tape flat inside it, shut the book, put another on top and leave it for a few hours/overnight. Then wind it back into the cassette, and wind it both ways a few times.

Be careful - the shiny part goes on the inside. Opposite of Reel-to-Reel.

Then, transfer the recording to another tape. There will probably be drop-outs on it, but this can't be helped. Never re-use a damaged tape!

Cheers,

Steve P

[paulsherwin]

If you carefully wind the chewed tape back into the housing then wind and rewind the tape a few times, it should flatten enough to play. As Steve says, there will still be audible dropouts, but the tape should feed through without problems.

If a tape has been mangled, this normally indicates mechanical problems in the player and it's likely to happen again, though as discussed in the other thread some brands of tape are much better than others.

Paul

[dsergeant]

To answer the original question, tape chewing is invariably caused by slipping belts in the player causing the take up spool not to be driven. To stop it happening replace the belt (it is usually fairly easy to see which one it is, slightly harder to strip it down to change it).

Dave

[DOFFERY]

There are many reasons for chewed tape , apart from the cassette itself, pre recorded tapes being one major problem. The take up drive varies from machine to machine from simple belt to the ridiculous small idler drive via the second motor, you really need to know the method of drive .
As for the cassette itself , if of great value just wind or rewind to the end & leave for sometime, in many cases it will hardly be noticed, recording on same tape can be a problem, thats the beauty of reel to reel.

Doffery.

[af024]

I've had old machine go into chew mode because the take-up torque was too high. Hard to believe I know. The symptom was that the tape rode further up (or down) the capstan/pinch wheel and cause edge creasing. When I backed the torque off, everything worked ok. I've had this on at least three machines. Exactly what the mechanism is for INCREASING torque over the years is beyond me. I would have thought that it would have backed off, but there you go.

Maybe the riding up/down problem is also exacerbated by a shiny/smooth/hard pinch wheel too.

As for getting the correct torque, well that's another matter. I had nothing professional to measure it, so I made a contraption in the remains of an empty cassette shell (just the wheels and casing), which caused the take-up to pull on an elastic band. I measured the stretch in an untampered, working machine and compared that reference when I adjusted the torque. Seemed to work anyway.

Regards,


Andy

[Studio263]

I find the most common cause is that the pinch roller has become too shiny, this allows the tape to wander off the end of the capstan and get mangled. This is a major shortcomming of the cassette system, ideally the pinch roller would have been on the non-metallic side of the tape (as it is in open reel models), that way it stays cleaner longer.

You can re-face the pinch roller with medium grade oxide paper, in almost all cases this restores satisfactory performance. Take it out of the machine to do this so you don't foul the mechanism with abrasive grit. Obviously don't over do it and be sure to keep the roller reasonably round and true. Once you've finished give it a good wipe over with IPA before re-fitting it.

Also make sure that the take-up torque is not excessive. The best tool to check this is a cassette-type torque meter but if you can't get one don't worry, use your fingers to "feel" how much force is there with the cassette removed. "Calibrate" them first by checking a few "good" machines. If the torque is excessive the first place to look is the play clutch, they can get gummed up, a good clean with IPA should solve that. Some models have a take-up motor, if the transistor that controls this goes short circuit you will end up with chewed up tapes.

Finally, give "dual capstan" decks (Tandberg, Sony, the original Beocord 5000 etc) extra care, these are all natural tape manglers if not in perfect condition and most have many very tricky adjustments to get right in order to make them workable. Not for the faint hearted for sure.

[ben]

a combination of things can often cause this.
as mentioned in the other thread, cheaper decks found in ghetto blasters and mini systems etc., handle the tape very badly (even from new!) and are to be avoided for serious use.

Apart from the loss of drive or torque on the take up spool, leading usually to immediate chewing, there' s also more intermittent chewing- if the pinch roller gets shiny or warped, the tape will ride and crease, and hence wind unevenly inside the casssette. As this happens, you will hear the audio coming and going and sound out of phase. As the take up spool fills, this uneven mass rubs against the inside of the cassette shell and jams - leading to what the Germans call 'bandsalat' !

[Focus Diode]

I've known a dirty pinch roller to cause this problem.

Personally, unless the tape has snapped, I wouldn't recommend cutting and splicing the tape which is extremely difficult with cassettes.

Brian

[Mike Phelan]

Another cause is the cold damp in a car radio cassette left outside in winter.

The slightest build-up of oxide on the capstan or pinch roller will snag the tape and cause a birds-nest.

[ben]

Originally Posted by Mike Phelan

The slightest build-up of oxide on the capstan or pinch roller will snag the tape and cause a birds-nest.

that's a bit of an exaggeration Mike!
usually the presence of oxide residues just leads to uneven passage of the tape over the pinch/capstan, but I've never seen the tape actually snag. For the tape to really tangle, either the take up is poor or missing or the pinch /capstan are sticky. This may come from home made splices made using sellotape which oozes, and also tapes left lying around may have spillages or contaminants.

[Mike Phelan]

Probably a touch of there hyperbole, Ben, agreed! I think the actual working surface of the capstan will remain fairly shiny until something from the tape does stick to it, in which case it only has to snag once.

When my video department window faced the loading bay used by the installers, there were not many weeks where one of that ilk did not knock at the door clutching a cassette that resembled spaghetti bolognese, followed by bringing me their machine with more spag bol wrapped around the capstan!

[ben]

Originally Posted by Mike Phelan

Probably a touch of there hyperbole, Ben, agreed! I think the actual working surface of the capstan will remain fairly shiny until something from the tape does stick to it, in which case it only has to snag once.

When my video department window faced the loading bay used by the installers, there were not many weeks where one of that ilk did not knock at the door clutching a cassette that resembled spaghetti bolognese, followed by bringing me their machine with more spag bol wrapped around the capstan!

You've reminded me of another common cassette problem. Tapes left in the car bouncing about always got slack inside as the spools moved, and if you tried to play them without taking up the slack first, then they'd really tangle and spew tape everywhere. I suppose that is neither the fault of the deck nor the cassette but bad user storage habits!

[Paul Stenning]

That's why cassette boxes have plastic pegs to stop the reels turning.

[Focus Diode]

I'm sure we've discussed this before, but the quality of the tape/case often has something to do with it. Pre-recorded double play tapes for example. They're liable to tighten until they spill their contents all over the place.

I've successfully solved the problem by putting such tapes in decent shells, TDK or Maxell for example.

Brian

[paulsherwin]

Originally Posted by Focus Diode

I'm sure we've discussed this before, but the quality of the tape/case often has something to do with it. Pre-recorded double play tapes for example. They're liable to tighten until they spill their contents all over the place.

I've successfully solved the problem by putting such tapes in decent shells, TDK or Maxell for example.

This is a good use for ancient TDK D cassettes. The tape in these is pretty undistinguished but the shell mechanics are excellent. They often crop up at car boot sales, in charity shops and on Freecycle.

Paul

[ben]

Originally Posted by Focus Diode

I'm sure we've discussed this before, but the quality of the tape/case often has something to do with it. Pre-recorded double play tapes for example. They're liable to tighten until they spill their contents all over the place. I've successfully solved the problem by putting such tapes in decent shells, TDK or Maxell for example.
Brian

To be honest I have always found prerecorded tapes to be pretty dire in terms of sound quality, doubtless due to the high speed duplication involved in their production. Unless the album in question is super- rare, it's probably not worth the effort to work on those cassettes, better to find the album on Lp or cd.

Of course, for saving prized or rare recordings any form of 'reel transplant' goes for me!

[Focus Diode]

Agreed Ben, I can't stand pre-recorded tapes. I used this as an example as the manufacturing quality of these tapes was dreadful. Most "Double Play" tapes were actually shorter than a C90!

In 1990 I purchased a batch of Dixons Ferric cassettes which were going very cheaply. I was short of cash and needed them to make some off air radio recordings. These had completely clear transparent cases and did give extremely good quality recordings.

Over a period they started to foul up due to sticking wheels and wouldn't REW or FF. I assumed a fault in the tape recorder, checked torque, cleaned heads etc until I realised only these tapes were affected. I found transferring the affected tapes to old TDK/Maxell shells solved the problem.

Should the reels be incompatible, it's possible to replace the reels (eg: the original to TDK etc ones), although this is quite fiddly!

Brian

[Alf Fisher]

Its not always the fault of the cassette recorder. Sometimes if part of a tape has been wound back and forth a number of times, it forms a random pile that becomes a bit too thick to run freely in the case. You can usually tell if one or both of the hubs are binding and don't turn easily. My cure was to gently squeeze the case between thumbs and fingers and flatten the pile. You should then be able turn the hubs much easier and they can run freely. Alternatively, you could fully rewind it, backwards and forwards, end -to-end until it forms a tidy pile.

Alf