This Instructable will teach you how to repair a common failure on very old cassette tapes. Only basic technical ability is required. You will need a toothpick, a new Q-tip, and a small piece of Velcro (hook and loop tape).
Step 1: The Little Spongy Thing Fell Out! (that's the Pressure Pad)
If you're here, it's because you're either a fan of cassettes or an interested party in what all this cassette hype is about. This is a quick and dirty fix I discovered to the missing pressure pad problem. Is it the "textbook" correct way? Nope. Will it get your old tape with a missing pressure pad working again? Yep!
DISCLAIMER.. This is not the expert approved way of doing this. This is a fix I found using something many hobbyist have at home that doesn't require you opening the tape. If you are lucky enough to have found the old pressure pad by all means glue it back in with a drop of crazy glue, just follow the instructions I gave for getting the tape out of your way to work.
What's the purpose of the pressure pad?
The pressure pad is used to press the tape against the machine's head which is what "reads" the tape. It doesn't require much force and its goal is just to get even tape contact onto the playback head. Not all machines require the cassette to have the pad in it but by default all cassettes have one. With the exception of some of the better cassette decks out there that mechanically compensate for the pressure pad, most will require the tape to have the pressure pad in it. All portables like Walkmans will need the tape to have the pressure pad.
What happens if the pressure pad is missing?
Your tape will sound dull on playback with no highs. Recordings will be incomplete and sound equally bad. Keep in mind a dull sounding cassette can be caused by a number of things, not just a missing pressure pad.
What tapes are affected by this problem?
In my experience this issue is mostly seen in older tapes, MUCH older tapes like stuff from the 60's and 70's. The glue that holds the little felt pad to the spring metal becomes brittle with age and gives up.
What does the pressure pad look like?
It's that little rectangular felt pad in pic 1. It can come in several different colors and is located under the tape in the center of the exposed side of the cassette. It's glued to a small spring metal plate. All cassettes are designed this way with only ONE exception, very old Memorex brand cassettes. They use a goofy sponge block with no spring plate that is a whole different issue to replace and not covered here. Any tape found that uses the big sponge block was made by Memorex. Pic 2 shows you a view of the tape missing its pressure pad.
Step 2: Velcro to the Rescue!
By necessity while rummaging around my junk drawer for crazy glue I realized that the loop side of Velcro, the soft fabric side, could make a usable felt pad replacement for a cassette. It's almost the right thickness, it has some give, and it's conveniently pre-glued so no need to mess with adhesives.
You don't need much. Use a good cassette to visually size up about how much you need to make your own replacement pressure pad. You'll need a tiny rectangle of the loop fabric side. make sure you don't get it from the edge as some Velcro fabrics have uneven edges.
Step 3: Pull Back, Clean, Insert
FIRST WASH YOUR HANDS WITH SOAP AND WATER AND THOROUGHLY DRY THEM! Oil and dirt are an enemy of tape.
Carefully pull out a loop of tape so you have room to work. This is best done with the tape wound to the end so you are handling the leader portion and not the part that actually has music on it. A toothpick works great for this as it's non magnetic. You don't want anything that's been accidentally magnetized near an audio tape.
With the tape out of the way, clean the area where the pressure pad used to be with a Q-tip. A dry one works to get any loose stuff off but one soaked in alcohol is better. Allow the alcohol to dry if you used that.
Next, use tweezers to grab the replacement pressure pad you made by the center of its fabric side. Just pinch some of the fibers in the center and it will grip it. Carefully peel off the paper exposing the adhesive side.
Finally, carefully place the pad you made onto the metal spring plate in the tape. The pad is rectangular and oriented a certain way. Use a good tape as a reference for how it's lined up. Gently press the pad down using the tips of the tweezers to assure good adhesive contact.
Step 4: Almost Done!
Pressure pad in place, carefully wind the tape you pulled out back into the shell. Be careful not to twist or knot the tape as it goes back into the shell.
The final step is something I felt necessary just from my experience with old tapes. Pop tape into machine and hit play for just a second. This will mash the head against the tape and your new pressure pad assuring a good adhesive bond. Now fast wind the tape all the way to one end and back. Some cassettes had a dry lubricant on the tape's backside and this will transfer some (if the tape had any) to the makeshift pressure pad.
Done! Enjoy your tape!
If you're interested in learning more about cassettes please check out my other Instructables on cassette repair and an in depth look at all the different cassette formulations.