Permanently Damaged Heads?

[dfgh11]

I was demagging recently when the power tripped just as I was near the record head. Now when I record or play back, with high frequencies I get pops that cut out slightly. I take it this head is shot?

[The Ghost of FM]

It depends on how strong the d-mag'er was that you used.

As an example; if you were using a TEAC/TASCAM d-mag during the accident, you might be able to redo the job with a stronger unit like the Han-demag model which outputs a much stronger field.

Good luck.

Cheers!

[dfgh11]

Thanks for the reply. It was a hand held model.But I'm not really sure how powerful it is. Is there anywhere I can get a more powerful demagging device? Sounds Silly but how about if I tape two demags together to try undo the damage?

[Peck]

I've been reading in a lot of interviews, that the han-d-mag is the only demagnitizer you should use. Who knows if that's true? Some reputable users though with a long history in analog recording... so I would think it is pretty good advice.

[cjacek]

Originally Posted by dfgh11

I was demagging recently when the power tripped just as I was near the record head.

What type of tape recorder were you demaging ?

[cjacek]

Originally Posted by dfgh11

It was a hand held model.But I'm not really sure how powerful it is. Is there anywhere I can get a more powerful demagging device? Sounds Silly but how about if I tape two demags together to try undo the damage?

If it was one of those radio shack type of wands and it doesn't look like it was a Han-D-Mag, which IS the most powerfull demagger around, .... and if the recorder in question has any value to you then get the Han-D-Mag (as Jeff "Ghost" suggested) and try it one more time. It is likely you might be able to pull the residual magnetism out. Taping two demags together may work as the magnetic field is not only at the tip but further out so doubling the magnetic power surely may work. That's just my theory tho so treat is as such.

[cjacek]

Originally Posted by Peck

I've been reading in a lot of interviews, that the han-d-mag is the only demagnitizer you should use. Who knows if that's true? Some reputable users though with a long history in analog recording... so I would think it is pretty good advice.

I know that Nakamichi recommended specifically against using the Han-D-Mag on their cassette decks for fear it was too strong and may cause damage to the head structures. I personally would not use the Han-D-Mag for cassette decks.

[dfgh11]

Thanks for responding.I'm using it on a fostex E-16 and it's of value, so I'll first try the two demags taed together and let you know what happens

[Beck]

Originally Posted by dfgh11

I was demagging recently when the power tripped just as I was near the record head.

My worst nightmare.

(Well actually the one where I wake up and there’s this old lady standing in my room in a black Victorian era dress is my worst nightmare. This has been a reoccurring dream since I was 17. Her name is Patricia Turner… I found her grave at a local cemetery after seeing her gravestone in one of my dreams. After all these years I’m still not sure what she wants… she never says a word. Women! even when they're dead you can't figure them out)

Anyway…

How close were you to the heads?

I've thought about plugging the demag into a UPS for this very reason.

I don’t know about tying two demagnetizers together. Two separate electromagnets won’t act the same as one bigger one, and could interact with each other unfavorably.

Han-D-Mag is your best bet to overcome the magnetic charge.

[cjacek]

I agree that a Han-D-Mag may be the best overall solution.

[dfgh11]

well I've further investigated the problem and the gargling sound on frequencies about 600hz and higher is only present on tracks 1 to 4. Would this be due to the demagging? I was having problems on tracks 1 and 16 before this whole thing happened, with loss of gain/frequencey, which was why I was demagging and going to realign in the first place.

[up-fiddler]

Originally Posted by Beck

(Well actually the one where I wake up and there’s this old lady standing in my room in a black Victorian era dress is my worst nightmare. This has been a reoccurring dream since I was 17. Her name is Patricia Turner… I found her grave at a local cemetery after seeing her gravestone in one of my dreams. After all these years I’m still not sure what she wants… she never says a word. Women! even when they're dead you can't figure them out)

Now I'm afraid to go to sleep!

BTW - Good advice on the cassette heads. I ruined a high end cassette deck about eight years ago by demagging with too much snuff.

[Beck]

Originally Posted by dfgh11

well I've further investigated the problem and the gargling sound on frequencies about 600hz and higher is only present on tracks 1 to 4. Would this be due to the demagging? I was having problems on tracks 1 and 16 before this whole thing happened, with loss of gain/frequencey, which was why I was demagging and going to realign in the first place.

Edge-tracks like 1 &16 on your E-16 will act up first as the head wears. However they will also get cruddy with oxide build-up more so than the others. Make sure you give them extra attention while scrubbing the heads with denatured alcohol or 90% or greater isopropyl alcohol.

The popping noises you describe sound magnetization related.

If you were using a small Radio Shack type degausser your chances of correcting the problem with a better degausser are quite good. Those smaller devices don’t do much for larger heads, but they can’t do much harm either.

The only degaussers I will use are the Han-D-Mag or the TEAC E-3.

Follow The procedure below from Paul White of SOS:

“The virgin's blood and goat's head are optional, but the way you wave the degausser about is pretty critical. Essentially it should be switched on about a metre from the machine, and brought towards the heads fairly slowly (over a period of 15 seconds or so) to allow the alternating magnetic field to build up gradually. Pass it slowly over the heads, ideally without actually touching them, and also pass it over the tape guides before withdrawing slowly to a safe distance (three feet is fine, if you don't do metric) before switching it off again. Never switch the thing on or off when close to the heads as you could leave a permanent magnetic charge on them, and always switch off the tape recorder before degaussing.”

[dfgh11]

Well the demagnetizer I was using was this one. http://www.studiospares.com/pd_12652...0DEGAUSSER.htm

[Beck]

That’s even pricier than the Han-D-Mag. Do you know what the degaussing power rating is for it? It should be listed in the manual or on the degausser itself in oersteds or gauss. The Han-D-Mag is about 350 oersteds.

[STUDERMADMAN]

If You Have A Full Size Tape Eraser,such As A Leever-rich Model Er-31.you Could Use It To Apply A Very Strong Magnetic Field But You Have To Do It Very Veryslowly And Smooth,whitch Is Not Easy With Heavey Erasers.if You Try This Make Sure Of The Mains Supply And Do It Sober!!.

[Beck]

Even safer... turn a Hand-D-Mag backwards. The flat end oposite the "probe" puts out more than twice the gauss... about 800 compared to 350 at the tip of the probe.

[MCI2424]

Originally Posted by dfgh11

well I've further investigated the problem and the gargling sound on frequencies about 600hz and higher is only present on tracks 1 to 4. Would this be due to the demagging? I was having problems on tracks 1 and 16 before this whole thing happened, with loss of gain/frequencey, which was why I was demagging and going to realign in the first place.

It sounds like you may have heads that need re-lapping at a minimum. The first hint is the outside tracks start to go away. The next hint is that random tracks go away and the last hint is when all trcks go away.

A little, alot, then totally.

Use some old tape you care nothing about.
Use a indelible ink black marker
color the record/playback head about the center (to the right, to the left including the center)

Let dry. Have a beer or something stronger to prepare you for the eventual outcome.


Thread tape and play for a very short length.



Remove tape and inspect the head you marked in black. The wear mark from the tape should be narrow, centered and the shape (top to bottom) should be straight. If the wear mark looks good, you suffer from tape alighnment (tape path I mean) BUT, tape path alignment has different symtoms like ALL tracks are messed up. IF the wear is "hourglass" shaped or uneven and relatively wide, then you need to remove the head block and send it to JRF for evaluation.

The good news: IF the heads are worn and gone, JRF will not charge you. IF the heads need re-lapping JRF will charge you like $275.00


The bad news: IF you get lucky and pay nothing, you need new heads. Damn.

IF you get unlucky, it will cost like $275 and you will need an alignment tape (like $135) to get the machine back to normal.

Now, you must define what is lucky and unlucky for you.


OR you can go ahead and clean the heads over and over again (I love this advice, it always kills me) and marvel at the fact that worn heads seem to come and go with every cleaning. People seem to keep the faith and clean, clean, clean.


The best sounding record/play head is the one that is about to wear through at any moment. That is asuming that the wear is not uneven and ground down.

[Beck]

The initial information gives every indication of a fault during the degaussing process, which produced signs consistent with significantly charged heads. (basic rules of troubleshooting anything form cars to PCs)

1. What was user doing immediately before malfunction was detected?
2. Is there a relationship – cause/effect between the action of the user and the new problem/s?
3. What known problems existed that need attention?

Advice on basic maintenance – cleaning and damaging is particularly appropriate on a home recording form, where many new owners of used equipment aren’t even aware that these procedures are necessary or how to carry them out.

Those of us who have been using analog tape machines for many years are quite familiar with the oxide buildup unique to edge-tracks.

Maintenance advice is repeated by many of us here because we’ve been there. The machines I’ve seen abandoned by their owners as “broken” due to sticky-shed alone… it’s just pitiful, and all for lack of knowing things we discuss here on a regular basis.

It may well be a given machine will ultimately require more than just routine maintenance. However, these basic steps are still best practices as first steps.

The basic stuff first… you can always tear your machine apart later.

You should find helpful, J. McKnight’s technical paper on demagnetizing, and a nice guide to maintenance from Ray Rayburn’s soundfirst.com

http://home.flash.net/%7Emrltapes/mcknight_demag.pdf

http://www.soundfirst.com/cleandemag.html

[MCI2424]

Originally Posted by Beck

The initial information gives every indication of a fault during the degaussing process, which produced signs consistent with significantly charged heads. (basic rules of troubleshooting anything form cars to PCs)

1. What was user doing immediately before malfunction was detected?
2. Is there a relationship – cause/effect between the action of the user and the new problem/s?
3. What known problems existed that need attention?

Advice on basic maintenance – cleaning and damaging is particularly appropriate on a home recording form, where many new owners of used equipment aren’t even aware that these procedures are necessary or how to carry them out.

Those of us who have been using analog tape machines for many years are quite familiar with the oxide buildup unique to edge-tracks.

Maintenance advice is repeated by many of us here because we’ve been there. The machines I’ve seen abandoned by their owners as “broken” due to sticky-shed alone… it’s just pitiful, and all for lack of knowing things we discuss here on a regular basis.

It may well be a given machine will ultimately require more than just routine maintenance. However, these basic steps are still best practices as first steps.

The basic stuff first… you can always tear your machine apart later.

You should find helpful, J. McKnight’s technical paper on demagnetizing, and a nice guide to maintenance from Ray Rayburn’s soundfirst.com

http://home.flash.net/%7Emrltapes/mcknight_demag.pdf

http://www.soundfirst.com/cleandemag.html

Initial infor was that tracks 1%16 were a problem. Degaussing was just a stepping stone to the tracks 1&4 problem. Worn heads act like this and everything you do to them SEEMS to change the problem.


It is very hard to magnatize heads like the fabled stories lead you to believe.

Even IF the heads were complete magnets, you would never have select tracks act strange.

People just havew to accept the fact that heads need re-lapping and replacement sometime in their useful life. Time certainly will not make this situation better, only worse. Since there are no new tape decks out there, I am guessing that the ones showing up on eBay are there for a reason. To get rid of old technology, because they don't work right, etc .


I expect that alot of questions in the future here will be about problems with magical dissapearing tracks and the best advice to be had here seems to be:



clean the heads. Demag the unit, clean the heads again and keep doing it because it is probably sticky-shed anyway.

Dirty heads are remarkably stable in their symptoms if you pay attention because oixide piled up stays piled up until it is removed.
Worn heads shift all over creation and will work fine, lose bass, lose treble and go away all together only to be fine after a cleaning, or waiting period. Worn heads are unpredictable and that is why they are so easy to diagnose if you pay attention.

[jpmorris]

Originally Posted by MCI2424

Initial infor was that tracks 1%16 were a problem. Degaussing was just a stepping stone to the tracks 1&4 problem. Worn heads act like this and everything you do to them SEEMS to change the problem.

Well we can probably establish whether the heads are chronically worn.
DFGH, do you think you can put up a closeup photo of the heads?

[Beck]

Fabled stories? Mythical now, is it? (me laughing and crying... Hey Dragon! Could we get one emoticon for this please???)

As I stated three days ago in post #13 above,

“Edge-tracks like 1 &16 on your E-16 will act up first as the head wears.”

So yes it could be symptoms of a worn head, but one must keep a cool head as we patiently and methodically follow industry standard diagnostic steps in the right order, escalating only as the simpler measure fail to remedy the problem/s.

Normal magnetic buildup occurs relatively evenly over time. However, sudden magnetization through a degaussing error is focused due to the small size of the probe. A tape head appears to be physically one piece, but it is not magnetically one piece. It should now be painfully clear (if it wasn’t before) why a demaging probe must be slowly waived over the head to degauss it thoroughly and evenly. If it was magnetically one, you could achieve degaussing by touching the probe to one corner.

It is a simple matter of physics that metal nearest the deqausser when power is lost would have a greater charge. A degausser creates a cyclically reversing magnetic field. If the alternating action stops close to the area being degaussed, that area will be charged with the last half-cycle before interruption. Areas further from the probe receive a weaker charge.

The induced magnetism follows the inverse square law as the device is moved away from the object being degaussed. Doubling the distance of the probe from the area of the head reduces the power to ¼ of what it is right at the tip. And we are talking tiny increments in distance here – millimeters. Magnetically speaking, the distance from one side of a tape head to the other is a long way. So yes, a group of tracks together could become more severely charged than the rest.

Now back to tape path cleaning – it’s the most important regular maintenance item on the list, and it is often neglected. No one on this forum has advocated cleaning as the only course of action, but simply the first course of action, and that it should be thorough. As in the case of sticky-shed a normal cleaning will not suffice. If you’ve never had to remove oxide shed from head relief slots at the edge-tracks with a toothpick and magnifying lens, well you just haven’t lived.

But even normal, uniform oxide buildup reduces tape-to-head contact to an unacceptable degree for serious recording. Narrower tracks and closely spaced tracks are more susceptible. So, an E-16 will present deterioration in audio performance due to oxide buildup sooner compared to a ¼” half-track using the same tape at the same speed. And again – the edge-tracks, the edge-tracks (say it with me) the edge-tracks… remember the edge-tracks – in this case 1 & 16. If bad tape has ever been run through this machine it is very likely the edge-tracks have never been fully cleared. Remember the toothpick… yeah, it gets that ugly and worse.

~Tim

[cjacek]

It's a process of careful elimination of the most basic / fundemental (but common) possible causes and then proceeding further, as Tim so elequently points out.

[Dr ZEE]

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[dfgh11]

Originally Posted by jpmorris

Well we can probably establish whether the heads are chronically worn.
DFGH, do you think you can put up a closeup photo of the heads?

Yeah I'll do that tonight. I'll also put up an audio clip so that you can hear what I hear. Any problems I was getting before hand with tracks were I think probably down to the fact I was using GP9 on a machine calibrated for 456. I've found now that the frequencies seem to be back, if I could only get rid of the 'gargling' sound I can get on with aligning it for GP9. I already have a calibration tape from JRF