I have enjoyed reading this topic as it takes me back to other days. I am a
life long broadcaster and have worked with cassette, reel-to-reel,
cartridge, eight track, and digital audio tapes. All of these types of tape
media have one big thing in common. They require lubrication to run
smoothly. The lubrication is applied to the tape itself when it is
manufactured. Hi end quality tape has lots of lubrication, and cheap low
end tape often has little or none. When tapes age, they dry out. This
results in a number of problems. The most significant result is the
lubrication is not as good, or it may even be totally rubbed off. Often an
old dry tape will begin to shed the oxide which holds the magnetic
recording. When this happens, it results in excessive drop outs, otherwise
degraded sound, and very dirty heads, capstan and pinch roller. The
squealing is mostly from the lack of lubrication. The tape just cannot pass
smoothly over the heads. The larger the heads, like the erase head on a
reel-to-reel, the worse the problem. Cassette tapes have one additional
problem. They have a pressure pad inside the case directly behind the part
of the shell that passes a tape across the play/record head. If this
pressure pad is in decent condition, the tape sounds better. However, if
the pressure pad has become worn or is missing altogether, the sound will be
awful, and squealing may also result. If the heads are dirty, they usually
don't squeal, they just cause degraded sound. If the pinch roller (rubber
wheel) is really dirty, the tape may skew or slip which will cause bad
sound. This doesn't normally cause tape squeal either. As one person
already wrote, a very worn tape head can cause squealing because the tape
doesn't travel smoothly over the misshapen head any longer. If the tape is
also old and dry, then it's just worse.
Unfortunately, there really aren't any great remedies. Cleaning the heads
can help sometimes. Though Tom is correct that over a long period of time
using alcohol on the pinch roller can glaze or degrade it, in practice, this
is not likely for the rare cleaning a consumer does. I wouldn't worry about
it. If the tape is the actual problem, instead of the heads, then you are
basically out of luck. You used to be able to buy a silicon spray which
could be used on heads to help an old tape get one or two more plays so it
could be copied to another medium, but I don't think the stuff is around
anymore. Radio Shack would be where I'd look. Baking the tape is an
option, but this is a tricky operation. Be aware that tape is highly
flammable. If you catch it on fire, you will have a much worse problem than
squealing tape. Another remedy I've heard, that was not mentioned on this
list, is to take a sponge, make sure it is only damp, and not dripping, and
put the sponge and the tape in a plastic bag over night. The moisture is
sometimes enough to get just a bit more out of the remaining lubrication to
get one more play.
If it is a NLS recorder, and it squeals on all tapes, then get it replaced.
This is an easy process. If the tape itself is bad, mark it in the
container so the library can replace it with a new recording. If it is your
personal tape, and none of the above works, or is worth the effort, just
throw it out. No medium lasts forever.
Bill
-----Original Message-----
From: VICUG-L: Visually Impaired Computer Users' Group List
[mailto:[log in to unmask]] On Behalf Of burg..
Sent: Monday, September 05, 2005 4:04 AM
To: [log in to unmask]
Subject: Re: squealing tapes
My experience with cassette tapes goes back to 1969. That experience causes
me to disagree with Dan. I relate the sound of squealing tapes to a tape
that is much worn. I do not know the exact cause. Perhaps it relates to
the cartridge in which the tape is housed.
It is always a good idea to clean tape heads and capstan drives on machines.
They will wear longer and they will not muffle the sound of the tape if they
are dirty. I use grain alcohol for this purpose. I wet a cue tip with the
alcohol and rub the wetted cotton on the heads and the
rubber of the capstan drive. Tom Burgunder
On Mon, 29 Aug 2005, .dan. wrote:
> It means the head is worn and the machine should be replaced. A
> temporary fix sometimes works. Without a tape in the machine put it
> into play and then advance both speed controls to full. Using a cloth
> press it against the wheel and shaft that are turning near the front
> of the opening for a few seconds to wipe any material from them. Then
> wipe the tape head which is a square thing protruding near the middle
> of the front of the tape opening to wipe any material that may have
> become attached. It is best to ask your lending library for a
> replacement even if the fix seems to work because the squeal will start
soon again.
>
> XB
> IC|XC
>
>
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VICUG-L is the Visually Impaired Computer User Group List.
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