June 26, 2017 - Robert John Hadfield

Strange Gasket Problems

This is a really rare issue caused by something meant to help.


Cassettes are little more than miniaturized versions of reel to reel tapes. Other than size, one of the most significant differences is the fact that cassettes are not “open reel.” With a cassette, the reels are hidden inside a housing rather than exposed like old reel players were.

With open reels, there is something of a cage to make sure the tape stays on the reel. But with cassettes, there is no such thing. Because it is inside a housing, the cassette tape theoretically can’t come off the reel. The sides of the housing itself hold the tape in place on the reel.

As the cassette spins inside the housing, the sides of the reel of tape are constantly rubbing against the inside of the cassette housing. If the tape doesn’t line up evenly on the reel itself, this can cause friction which could potentially damage the tape and put strain on the motors.

So to reduce the friction inside the cassette housing, and ensure that the tape lines up smoothly on the reel, most cassettes have a thin gasket on each side of the reel inside the housing. It’s no thicker than a piece of paper.

And although you would never suspect it, that gasket can cause a problem with tape playback. This is VERY rare, but we have seen it a few times over the years. And I decided to write this article because we had a tape come in last week with this problem.

The gaskets on either side of the tape are not connected to anything. But they sit in place because they are cut to align to certain physical characteristics of the inside of the tape. However, they can float a little bit. And every once in a while, that gasket will move into an unwanted position.

If you look at this picture, you will see a little dark line along the edge of the reel. That dark lines isn’t supposed to be there. It’s actually the edge of the gasket that has somehow pushed slightly through the reel opening in the housing. And although the gasket reduces friction inside the housing, when it does this, it adds friction. In some cases this actually causes the tape to drag.


Here we have another photo where the you can see clearly how a gasket has been bent as it was pulled into the reel.


If you flatten it out with your fingers, you can usually set it back in place and remedy the problem. But for the most part, your tape will work just fine without it. So it can be completely removed if needed.

In this case we simply re-aligned the gasket and closed it back up. You can see in this “after” photo that the gasket is no longer poking through the reel opening.


It’s a rare issue to be sure, but it’s one of those weird little things you learn when you have run a business like this for a couple of decades. After two decades you know what to look for.

Sometimes things that are meant to help, can cause problems.

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