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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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Tape head demagnetization
My car (built-in) tape player seems to be getting strange in its
volume. Associated radio is fine, tape volume is down. I thought that I should demag the tale head. But, the opening is only barely big enough to insert a tape, and my 120V 60Hz demagger has a 1/2" long tip at 1/3" diameter, affixed on the end of a tube that is at least 1" diameter so there is no way to get the demagger tip anywhere near the tape head. I could maybe tape a large nail to the end of the existing tip, and reach the vicinity of the head, but I don't think that will so anything. I don't know what the magnetic structure is under/inside the head, but assume it is shaped to deliberately have flux going outside the head. It's not worth it to make a coil small enough to fit into the opening. I understand there are demagnetizing tapes available, but I am cheap and don't want to spring for the $$ unless I am reasonably (66+%) sure it will work. Thoughts, ideas, polite suggestions. |
#2
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Tape head demagnetization
A magnetized head will cause loss of high frequencies long before there's a
drop in volume. The deck probably has some other problem. |
#3
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Tape head demagnetization
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#4
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Tape head demagnetization
On Nov 24, 5:05*pm, "Gareth Magennis"
wrote: "hr(bob) " wrote in message ... My car (built-in) tape player seems to be getting strange in its volume. *Associated radio is fine, tape volume is down. *I thought that I should demag the tale head. *But, the opening is only barely big enough to insert a tape, and my 120V 60Hz demagger has a 1/2" long tip at 1/3" diameter, affixed on the end of a tube that is at least 1" diameter so there is no way to get the demagger tip anywhere near the tape head. *I could maybe tape a large nail to the end of the existing tip, and reach the vicinity of the head, but I don't think that will so anything. *I don't know what the magnetic structure is under/inside the head, but assume it is shaped to deliberately have flux going outside the head. *It's not worth it to make a coil small enough to fit into the opening. *I understand there are demagnetizing tapes available, but I am cheap and don't want to spring for the $$ unless I am reasonably (66+%) sure it will work. Thoughts, ideas, polite suggestions. My initial thoughts are that tape heads that need demagnetising do not generally exhibit the kind of extreme symptoms you are experiencing. I would forget demagnetising as a solution right now, and try and establish the real cause of the dramatic loss of level. Gareth.- Hide quoted text - - Show quoted text - Thanks Bill and Gareth, OK - that's two votes against demagnetizing, plus I was skeptical myself. So, now I have to decide whether to move my tapes to CD's, or tear into a 10 year old car radio/tape player /cd player. I think it will be easier to move a few tapes to CDs than tear up the car radio. |
#6
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Tape head demagnetization
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#7
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Tape head demagnetization
On Nov 24, 3:27*pm, "hr(bob) "
wrote: My car (built-in) tape player seems to be getting strange in its volume. *Associated radio is fine, tape volume is down. *I thought that I should demag the tale head. *But, the opening is only barely big enough to insert a tape, and my 120V 60Hz demagger has a 1/2" long tip at 1/3" diameter, affixed on the end of a tube that is at least 1" diameter so there is no way to get the demagger tip anywhere near the tape head. *I could maybe tape a large nail to the end of the existing tip, and reach the vicinity of the head, but I don't think that will so anything. *I don't know what the magnetic structure is under/inside the head, but assume it is shaped to deliberately have flux going outside the head. *It's not worth it to make a coil small enough to fit into the opening. *I understand there are demagnetizing tapes available, but I am cheap and don't want to spring for the $$ unless I am reasonably (66+%) sure it will work. Thoughts, ideas, polite suggestions. loss of volume? doesn't that mean gunk building up that keeps the tape too far away form the head? Or, mean some component is lost? like a coupling cap that has seen better days? Or, something as simple as one of the wiring connections in the cabling has gone high resistance. Sadly, my favorite tapes were made during the era of poor mylar coating and have all turned 'squeaky' and unplayable! I wish I could have transferred them before they died, but hindsight. |
#8
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Tape head demagnetization
On 11/24/2012 4:35 PM, Robert Macy wrote:
On Nov 24, 3:27 pm, "hr(bob) wrote: My car (built-in) tape player seems to be getting strange in its volume. Associated radio is fine, tape volume is down. I thought that I should demag the tale head. But, the opening is only barely big enough to insert a tape, and my 120V 60Hz demagger has a 1/2" long tip at 1/3" diameter, affixed on the end of a tube that is at least 1" diameter so there is no way to get the demagger tip anywhere near the tape head. I could maybe tape a large nail to the end of the existing tip, and reach the vicinity of the head, but I don't think that will so anything. I don't know what the magnetic structure is under/inside the head, but assume it is shaped to deliberately have flux going outside the head. It's not worth it to make a coil small enough to fit into the opening. I understand there are demagnetizing tapes available, but I am cheap and don't want to spring for the $$ unless I am reasonably (66+%) sure it will work. Thoughts, ideas, polite suggestions. loss of volume? doesn't that mean gunk building up that keeps the tape too far away form the head? Or, mean some component is lost? like a coupling cap that has seen better days? Or, something as simple as one of the wiring connections in the cabling has gone high resistance. Sadly, my favorite tapes were made during the era of poor mylar coating and have all turned 'squeaky' and unplayable! I wish I could have transferred them before they died, but hindsight. I'd give up on head demagnetizing. It's not likely the problem. And you're more likely to magnetize it with the demagnetizer unless you disassemble the thing so you can get at it. Tape players don't last in cars. I've only had two CD players and they were worse. The heat, outgassing of plastics, dirt, etc. get all over the optical and mechanical stuff. Luckily, my last player has a USB slot and a Flash Card slot. It won't play a CD any more, but the SD card works fine. As for old tapes... If you have rare music, you're pretty much screwed. If you have popular stuff, there's an option. Go to the library, check out a CD. Copy it back to the tape. If you bought the tape, you own the license to play it. The nitpickers will argue about it, but I think you're on solid moral and legal ground to refresh the media. |
#9
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Tape head demagnetization
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#11
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Tape head demagnetization
"Charlie+" wrote in message
... On Sat, 24 Nov 2012 16:35:30 -0800 (PST), Robert Macy wrote as underneath my scribble : A trick I found for this squeaky problem to do a one time transfer was to play them as cold as possible, unfortunately just freezing the tapes doesnt last long enough - always thaught a head heatsink to a deepfrozen al or cu block might do the trick but I never tried it!! I just caught mine early enough! Mine were BASF Sadly, my favorite tapes were made during the era of poor mylar coating and have all turned 'squeaky' and unplayable! I wish I could have transferred them before they died, but hindsight. Try this method. Put a "squeaky" tape on a metal tray, and put it in a 150 degree oven (NO HOTTER!!) for about 1 hour. It will reactivate the binders and lubricants and when you play it, TRANSFER it to another medium on first play. Works for old reel to reel tapes. Google is your friend. http://en.wikipedia.org/wiki/Tape_baking |
#12
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Tape head demagnetization
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#13
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Tape head demagnetization
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#14
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Tape head demagnetization
On Sat, 24 Nov 2012 15:21:52 -0800 (PST), "hr(bob) "
wrote: Thanks Bill and Gareth, OK - that's two votes against demagnetizing, plus I was skeptical myself. So, now I have to decide whether to move my tapes to CD's, or tear into a 10 year old car radio/tape player /cd player. I think it will be easier to move a few tapes to CDs than tear up the car radio. Lucky you are, over 200 to transfer have i. ?-) |
#15
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Tape head demagnetization
On Sat, 24 Nov 2012 16:35:30 -0800 (PST), Robert Macy
wrote: On Nov 24, 3:27*pm, "hr(bob) " wrote: My car (built-in) tape player seems to be getting strange in its volume. *Associated radio is fine, tape volume is down. *I thought that I should demag the tale head. *But, the opening is only barely big enough to insert a tape, and my 120V 60Hz demagger has a 1/2" long tip at 1/3" diameter, affixed on the end of a tube that is at least 1" diameter so there is no way to get the demagger tip anywhere near the tape head. *I could maybe tape a large nail to the end of the existing tip, and reach the vicinity of the head, but I don't think that will so anything. *I don't know what the magnetic structure is under/inside the head, but assume it is shaped to deliberately have flux going outside the head. *It's not worth it to make a coil small enough to fit into the opening. *I understand there are demagnetizing tapes available, but I am cheap and don't want to spring for the $$ unless I am reasonably (66+%) sure it will work. Thoughts, ideas, polite suggestions. loss of volume? doesn't that mean gunk building up that keeps the tape too far away form the head? Or, mean some component is lost? like a coupling cap that has seen better days? Or, something as simple as one of the wiring connections in the cabling has gone high resistance. Sadly, my favorite tapes were made during the era of poor mylar coating and have all turned 'squeaky' and unplayable! I wish I could have transferred them before they died, but hindsight. Depending on your tastes, some might be available now in CD or MP3 format. You may have to buy a lot more than what you have to get all you want. I have a lot of old music of the 1950s to 1970s range and an interesting bit outside that range. Not all digital yet. You know how to find me. ?-) |
#16
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Tape head demagnetization
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#17
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Tape head demagnetization
On Nov 25, 11:09*am, "Klaatu" wrote:
"Charlie+" wrote in message ... On Sat, 24 Nov 2012 16:35:30 -0800 (PST), Robert Macy wrote as underneath my scribble : A trick I found for this squeaky problem to do a one time transfer was to play them as cold as possible, *unfortunately just freezing the tapes doesnt last long enough - always thaught a *head heatsink to a deepfrozen al or cu block might do the trick but I never tried it!! *I just caught mine early enough! * Mine were BASF Sadly, my favorite tapes were made during the era of poor mylar coating and have all turned 'squeaky' and unplayable! *I wish I could have transferred them before they died, but hindsight. Try this method. *Put a "squeaky" tape on a metal tray, and put it in a 150 degree oven (NO HOTTER!!) for about 1 hour. *It will reactivate the binders and lubricants and when you play it, TRANSFER it to another medium on first play. *Works for old reel to reel tapes. *Google is your friend.http://en.wikipedia.org/wiki/Tape_baking Wow! Great tidbit! |
#18
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Tape head demagnetization
Sadly, my favorite tapes were made during the era of poor mylar coating and have all turned 'squeaky' and unplayable! I wish I could have transferred them before they died, but hindsight. A trick I found for this squeaky problem to do a one time transfer was to play them as cold as possible, unfortunately just freezing the tapes doesnt last long enough - always thaught a head heatsink to a deepfrozen al or cu block might do the trick but I never tried it!! I just caught mine early enough! Mine were BASF I don't know if it's the same problem you're referring to, but I do know that a lot of reel-to-reel tapes made several decades ago suffer from a problem known as "sticky-shed syndrome". http://en.wikipedia.org/wiki/Sticky-shed_syndrome There's no permanent cure, but it's often possible to restore such tapes to playability (at least temporarily) by removing moisture from the tape/binder. This can be done by "baking" the tape at an elevated temperature, or by storing the tapes in a temperature-and-humidity- controlled environment for a period of time. Some people have tried lubricating the tape just before playing it (with alcohol, and I think I've heard of people using a light silicone oil as well). You might want to select one or two "sticky" tapes, and then doing a gentle bake (possible heat-and-time schedules are in the Wikipedia article), or put them in a sealed Tupperware container with several large (and recently-baked) silica-gel moisture-absorbing packs for a month or two. See if getting the absorbed moisture out of the binder restores the tapes to a playable condition... if so, play them and digitize them! I had the master and mix tapes for an album my wife recorded in the late 1970's baked and transcribed, some years ago... the process worked and we were able to recover the album and transfer it to CD. Without baking, it would have been a lost cause, I think. -- Dave Platt AE6EO Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
#19
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Tape head demagnetization
On Sat, 24 Nov 2012 14:27:55 -0800 (PST), "hr(bob) "
put finger to keyboard and composed: My car (built-in) tape player seems to be getting strange in its volume. Associated radio is fine, tape volume is down. I thought that I should demag the tale head. But, the opening is only barely big enough to insert a tape,... Just to offer a different perspective, I onced repaired a Fujitsu Ten auto-reverse car cassette player with the same symptom as yours. The problem turned out to be a small dirty multipole switch. I'm a bit hazy on the details, but ISTR that there were two head circuits, and a different circuit was selected in forward and reverse mode. As for demagnetising the head, I have a cassette tape with a built-in battery powered demagnetiser that automatically activates when you press the play button while the player is unpowered. It looks something like this ... http://farm3.static.flickr.com/2023/...ee2ffb7d96.jpg - Franc Zabkar -- Please remove one 'i' from my address when replying by email. |
#20
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Tape head demagnetization
"William Sommerwerck" wrote:
A magnetized head will cause loss of high frequencies long before there's a drop in volume. The deck probably has some other problem. Also true of a dirty head for the most part with possible left right issues. A magnetized head can ruin tapes HF. Greg |
#21
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Tape head demagnetization
If it's possible to see the head's tape surface from outside, a bright light
may be helpful to closely examine the surface.. any signs that the surface is worn/wavy indicates that the head is worn out. I never owned a radio/tape player where the volume was equal for both, but if the volume is very limited for tapes, checking the head surface for either dirt or wear would be worthwhile. Extending the reach of a demagnitizer may be possible (there are some types with numerous interchangeable tips) using a piece of steel rod (aligned end-to-end if the existing tip isn't removable), but the head surface should be protected from contact by the end of the rod (thick paint coating, nail polish, thin tape etc). -- Cheers, WB .............. "hr(bob) " wrote in message ... My car (built-in) tape player seems to be getting strange in its volume. Associated radio is fine, tape volume is down. I thought that I should demag the tale head. But, the opening is only barely big enough to insert a tape, and my 120V 60Hz demagger has a 1/2" long tip at 1/3" diameter, affixed on the end of a tube that is at least 1" diameter so there is no way to get the demagger tip anywhere near the tape head. I could maybe tape a large nail to the end of the existing tip, and reach the vicinity of the head, but I don't think that will so anything. I don't know what the magnetic structure is under/inside the head, but assume it is shaped to deliberately have flux going outside the head. It's not worth it to make a coil small enough to fit into the opening. I understand there are demagnetizing tapes available, but I am cheap and don't want to spring for the $$ unless I am reasonably (66+%) sure it will work. Thoughts, ideas, polite suggestions. |
#22
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Tape head demagnetization
On Sat, 24 Nov 2012 16:35:30 -0800 (PST), Robert Macy
wrote: On Nov 24, 3:27*pm, "hr(bob) " wrote: My car (built-in) tape player seems to be getting strange in its volume. *Associated radio is fine, tape volume is down. *I thought that I should demag the tale head. *But, the opening is only barely big enough to insert a tape, and my 120V 60Hz demagger has a 1/2" long tip at 1/3" diameter, affixed on the end of a tube that is at least 1" diameter so there is no way to get the demagger tip anywhere near the tape head. *I could maybe tape a large nail to the end of the existing tip, and reach the vicinity of the head, but I don't think that will so anything. *I don't know what the magnetic structure is under/inside the head, but assume it is shaped to deliberately have flux going outside the head. *It's not worth it to make a coil small enough to fit into the opening. *I understand there are demagnetizing tapes available, but I am cheap and don't want to spring for the $$ unless I am reasonably (66+%) sure it will work. Thoughts, ideas, polite suggestions. loss of volume? doesn't that mean gunk building up that keeps the tape too far away form the head? Or, mean some component is lost? like a coupling cap that has seen better days? Or, something as simple as one of the wiring connections in the cabling has gone high resistance. Sadly, my favorite tapes were made during the era of poor mylar coating and have all turned 'squeaky' and unplayable! I wish I could have transferred them before they died, but hindsight. Much of the audible 'squeek' noise may be the fault of the housing, rather than the tape itself. Transfering the reels to a new case may fix that. Labels can also be transfered, if the fix works. In some instances, the case was defective on first transfer, so the audible jitter was included in that transfer - no way around this. RL |
#23
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Tape head demagnetization
On 11/25/2012 08:52 PM, Cydrome Leader wrote:
"hr(bob) " wrote: My car (built-in) tape player seems to be getting strange in its volume. Associated radio is fine, tape volume is down. I thought that I should demag the tale head. But, the opening is only barely big enough to insert a tape, and my 120V 60Hz demagger has a 1/2" long tip at 1/3" diameter, affixed on the end of a tube that is at least 1" diameter so there is no way to get the demagger tip anywhere near the tape head. I could maybe tape a large nail to the end of the existing tip, and reach the vicinity of the head, but I don't think that will so anything. I don't know what the magnetic structure is under/inside the head, but assume it is shaped to deliberately have flux going outside the head. It's not worth it to make a coil small enough to fit into the opening. I understand there are demagnetizing tapes available, but I am cheap and don't want to spring for the $$ unless I am reasonably (66+%) sure it will work. Thoughts, ideas, polite suggestions. I'd clean the head and capstan first, then worry about degaussing things. You mention the capstan, I would also check the rubber roll very carefully. After years it often gets little tears in the rubber and it may be deformed and therefor not be guiding the tape correctly anymore. They are cheap and relatively easy to replace. Greetings, Rene |
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