Yes, both audio and video quality deteriorate with age.

You've tested the player with a known good tape?

Yes, my cassette audio tapes started playing very erratically. I had not listened to any for a long while but they just kept on deteriorating.

jim-
I just had some 30-year-old VHS tapes converted to a DVD and the sound and picture were still decent. While you may have lost the sound through deterioration, I am suspicious that all your tapes have completely lost all sound. I think it could be a fault of the player or the setup. For example, the connecting cables may not be plugged in to the correct jacks, or the cable plugs or jacks could be defective on either end. The first thing to do is plug a headphone jack into the player to see if you get sound that way. Also, be aware that the sound track on videotapes runs along one of the outer edges, so, if the tracking of the player is off and there's no adjustment, the player won't be able to pick up the sound. Or the player's sound circuit could be bad.

If none of these suggestions help, try playing several of these tapes in a player that you know works correctly.

I used the same one over and over again for daily taping for 10 years until recently. It is fine. I hope they play correctly on another player.

In addition to the magnetic field gets weakened. The plastic tape can get brittle and break.

Transfer everything to CDs or DVDs.

dcarch

I am no scientist or engineer, but my understanding is there is an emulsion, gelatin solution , on one side of the tape which is present to record audio and video. It is when this medium begins to fail or does fail that tapes become unreliable. Age, heat, and cold are the main enemies of the emulsion.

The tape physically is nothing more than a transporter of the emulsion across the heads of the electronic device.

DA

Also if you're interested.

Media preservation

The magnitude of the problem of magnetic tape deterioration is just starting to be realized. According to some research, there is a good chance that magnetic tape older than 10 years will deteriorate. The threat comes from several sources, but the largest threat is chemical in nature, coming from the breakdown of the binder, or glue, that holds the magnetic particles to the polyester base of the tape. As this occurs, the tape often gets coated with a tenacious adhesive that makes it extremely difficult to play.Tape which has been stored in hot, humid conditions is particularly vulnerable to this phenomenon. In some cases the problem can be so severe that the magnetic material literally falls off or sheds from the base, leaving a pile of dust and clear backing. Before the problem becomes so advanced, archivists can bake the tape and make a new copy. Alternately, a digitally encoded copy of the tape can be made, so that its content can be preserved indefinitely as a digital data file.

Here is a link that might be useful: Media preservation

One thing few people realizes, record/playback head in your machine overtime can be magnetized a little, and when that happens, it can slowly erase your reecorded material.

You need to get a playback head demagnetizer to demagnetize the head once in a while.

dcarch

I'd like to hear from the original poster on whether he has had any success using the advice provided here....