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firebirdta84
March 16th, 2015, 08:41 PM
I posted this question on tapeheads.net, hoping to hear from some audio tape restoration specialists there.

I posted some interesting pictures of the residue there, so it might be worth a look.

http://www.tapeheads.net/showthread.php?t=39125

However, if anyone here has any feedback on this topic, I'd love receive that.

Thanks always,
-AJ

Chuck(G)
March 16th, 2015, 09:43 PM
I'm sure that the audio tape folks will tell you that you need to bake the tape. It's a time-tested procedure.

Uniballer
March 17th, 2015, 05:13 AM
Can you bake tape when it is in the cartridge? Even at an elevated temperature, can the humidity get out of the tape without the cartridge melting/deforming? Or are you thinking in terms of a specialized rig to blow warm, dry air through the head access opening? Or removing the tape from the cartridge before baking?

NeXT
March 17th, 2015, 07:49 AM
I've seen people bake umatic cartridges so a QIC tape shouldn't be any worse off.

Chuck(G)
March 17th, 2015, 08:21 AM
I'd think that anything that has active air circulation and good thermostatic control will do the job. I believe that Al uses a food dehydrator. My own rig is custom-built. The minimum magic temperature for tapes seems to be about 58C for a few hours (or days).

Al Kossow
March 17th, 2015, 08:56 AM
Can you bake tape when it is in the cartridge?

Yes, i've done a few hundred of them. I use a commercial food dryer, pop the plastic cover, remove the band, and
unroll the tape so that it is not under tension. then put the bottom plate and reel on the metal rack. 24hrs at the
same temp Chuck has recomended.

bear
March 17th, 2015, 01:16 PM
Al just described my exact process as well.

firebirdta84
March 18th, 2015, 09:06 PM
Thanks for these suggestions, everyone. I've read up on tape baking, and so this is what I was planning on doing if I saw any sticky-shed syndrome signs off the dull side (maybe combined with Al's suggestions of Tyvek on the bollards and/or pin by the read head. (http://marc.info/?l=classiccmp&m=140918666216390&w=2))

This tape has no signs of that, however, only the foreign residue left from the band where the band was in contact with the tape for 25+ years.

To be more specific, only about a 8-inch section in the place/position where the tape was sitting for 25+ years is affected by this, not the whole tape, and the residue is only on the sections where the belt rests against the tape read surface wound on each of the reels.

If the tapes were stored rewound all the way, this problem would not matter, because any residue would be before the "data start" single hole mark, and only on the leader, where there is no data.

However, if the tapes were stored where the tape position is where the data is written, then this is a problem. This is the exact case of the tape I use as an example above.

Interestingly enough, nobody has responded yet on the tapeheads.net forum.

So, then, maybe the baking will cause the residue to drop off and away, or become soft enough to be easy to wipe off with a Q-tip. Of course, I would have to lay the tape in the dehydrator in such a way that the affected sections are not wound around either of the reels, so that the residue is freely exposed.

Any additional thoughts from this group before I pursue that idea?

Chuck(G)
March 18th, 2015, 10:14 PM
Are you certain that the residue is from the belt, or, more likely, that the belt has removed oxide?

firebirdta84
March 18th, 2015, 11:54 PM
Chuck,

This is an EXCELLENT question...and quite frankly, before you asked, I hadn't even considered the belt removing the oxide as an option. So, I suppose I would need a really high-grade high-power stereo microscope to see whether these are raised spots or depressions, in order to really tell, but here's what I can determine with the meager tools that I do have.

Using a 60x magnifier and light attachment to my iPhone, I see this image of beginning edge of area of the tape affected by the belt contact. We really can't tell, and a side profile of the edge of the tape is useless with this low quality magnifier, as it has no depth to see whether these are raised areas or depressed areas.
23275

Now, thanks to you and others on a previous thread on this forum (http://www.vintage-computer.com/vcforum/showthread.php?46350-The-best-hardware-for-reading-20Mb-QIC-11-tapes/page2&highlight=kyread), I got myself some Kyread SDF-130A (http://www.magneticdeveloper.com/magnetic-developer/dropper-2oz) solution. I've applied this to the area of the tape right on the edge of the area affected by the belt.

On the magnified shot, the kyread solution obscures the mark left by the belt, but I can still just where it begins with the naked eye. I've marked the delineation here:
23276

And then, this is more how it looks with the naked eye under regular lighting.
23277

And then, I applied the Kyread to the belt itself, in the area where it was against the tape. The Kyread doesn't seem to have anything special going on in the area where I would expect that "data line" could be.
23278

Of course, all of this doesn't mean that the pulling away of the oxide still didn't happen, and can affect it in a way that the Kyread doesn't display using this method, but it's encouraging that this stuff might just be residue on the tape itself, and the magnetic signal is still under there intact.

As always, I love the responses here. This is a great discussion for me.

Thanks again,
-AJ

Chuck(G)
March 19th, 2015, 07:32 AM
Well, the belts themselves are pretty much a polyurethane formulation. Contacts at Imation state that the belts are punched as rings from a flat sheet of PU, then a special machine twists them into their final cylindrical shape and applies them. He tried to find the "manual" version of the belt application tool in their labs, but turned up nothing. You can see this annulus-to-cylinder transition in reverse by taking a fairly fresh belt and boiling it for a few minutes in water--the belt reverts to a ring shape.

The next thing that I'd try would be to take some 91% isopropanol and, with a clean tissue soaked in it, wipe both the discolored area on the belt and the corresponding area on the tape. See which one sheds. I'm of the opinion that it's the tape that's shedding.

Al Kossow
March 19th, 2015, 08:59 AM
I hadn't even considered the belt removing the oxide as an option.

That is EXACTLY what is happening. The 3M cartridge design is broken in that the belt contacts the OXIDE side of the tape
and not the backing. As the belt dries out, it binds to the tape binder on the oxide side gluing the binder to the belt. If you
are unlucky, the tape wasn't rewound into the BOT/EOT zone and it lifts the binder in the data area. Even if it is in the BOT/EOT
zone, you can end up with a situation where so much binder is gone that it confuses the EOT/BOT optical sensors. Neither Chuck
nor I have come up with a way to cover the bare area up enough to fool the optical sensors.

Chuck(G)
March 19th, 2015, 10:27 AM
I've thought about, but not tried 9-track BOT/EOT sense tape. They shouldn't stick to the tape inappropriately. There also the audio tape variety--all 1/4"

firebirdta84
March 19th, 2015, 11:59 AM
Wow, guys, thanks. This is very eye-opening for me.

So, can anyone comment on the picture that posted where the Kyread shows what appears to be a good magnetic signal even into the area of the tape that was affected by the belt?

bear
March 19th, 2015, 12:27 PM
I have only empirical evidence to offer. I have not studied this scientifically, but I have literally hundreds of tapes where this has happened, and my conclusion is that the majority of what is going on there is that the belt is leaving residue on the tape. Most of the read errors I have encountered on those parts of the tapes seem to be due to increased drag over the head (including sticky build-up on the head pulling oxide off that way), or having the oxide not in perfect contact with the head (due to the film of residue).

firebirdta84
March 19th, 2015, 12:50 PM
my conclusion is that the majority of what is going on there is that the belt is leaving residue on the tape.

Thanks for that, Bear. I appreciate the varied input from everyone here.

Bear, have you tried baking the tape, and observing the area where the residue may be, to see if it drips off, or becomes easier to wipe off in that heated state, either with a dry Q-tip or one with Isopropyl Alcohol?

Something like this is what I'm thinking of trying next, given everyone's feedback. If it is this, I stand a chance at restoring the tape enough to read it. If not, the oxide is already damaged, and then there is nothing to loose in this process.

Chuck(G)
March 19th, 2015, 02:08 PM
If it really is residue on the tape in this case, then another approach might be to scrape the residue off. Note that 9-track drives usually use a sharp ceramic blade to clean the tape; tape cleaning machines also do this--mine has a carbide blade to do this.

Al Kossow
March 19th, 2015, 02:26 PM
wipe off in that heated state, either with a dry Q-tip or one with Isopropyl Alcohol?


REALLY DANGEROUS to use alcohol. The binder is thin, and it is really easy to wipe right through it.

Common problem is shed buildup on the tape at the points where the tape serpenines. It is very difficult to remove.
All I've ended up doing is smearing it out, which sometimes is enough to read the block, but it often wipes out an
adjacent track.

Al Kossow
March 19th, 2015, 02:27 PM
If it is this, I stand a chance at restoring the tape enough to read it.

are you using a Tandberg tape drive?

firebirdta84
March 19th, 2015, 04:21 PM
are you using a Tandberg tape drive?

Yes, Al, I am using the TDC-3620 model you recommended. So far, it has been wonderful. Thank you for that.


REALLY DANGEROUS to use alcohol. The binder is thin, and it is really easy to wipe right through it.

I will heed this warning, Al, thank you.

bear
March 19th, 2015, 11:32 PM
I second that. Isopropyl is a disaster on a QIC.

My gut feeling has been that very slowly winding a tape manually to cause a deteriorated belt to peel off indirectly (rather then trying to directly pull the belt off) keeps the oxide more intact. It could just be that the few I pulled straight off were in worse shape. Other than that, I have no suggestions at this time on how to deal with these spots.

Chuck(G)
March 20th, 2015, 10:20 AM
So try isopropanol on the marked area on the belt. There, you've got nothing to lose.

aplmak
December 13th, 2017, 06:32 AM
I know this is an old thread.... but this is a pretty cool drop in replacement for the QIC 1/4 tape drive... for those with SCSI... I suppose with MFM a SCSI converter board I remember seeing may work?? Not too sure how you would adapt this to other than SCSI interface...

http://www.reactivedata.com/Products/SCSI_Bridge_Emulators_to_CF/CF2SCSI%20-%20SCSIFLASH-Rosemount_QIC_Tape_Drive_to_CF/index.php

mloewen
February 28th, 2019, 04:14 PM
To continue this old thread, I have a couple of HP 88140LC cartridge tapes which I would like to try and resurrect. These are NIB, but the tension bands have deteriorated. In two other cartridges, I had replaced the tension bands with 6" plastibands, but it appears that the old bands may have pulled some of the oxide layer off the tape. These HP tapes are preformatted, and a normal DC600A tape will not work in a 9144A drive. There also doesn't appear to be any way for mere mortals to format such a tape.

Before I start on these next two, is there anything I could use to gently remove a stuck tension band from the tape without destroying the oxide layer? I've seen mention of isopropyl alcohol (and recommendations against it), as well as WD-40. Has anyone successfully done this on an HP tape?

Chuck(G)
February 28th, 2019, 04:52 PM
Dunno, have you tried baking the tape?

mloewen
February 28th, 2019, 05:12 PM
Dunno, have you tried baking the tape?

I have not - not currently set up for it. Do you think that would unstick the tension band from the tape?

Chuck(G)
February 28th, 2019, 05:50 PM
Well, it's the least invasive thing to try. The belt itself is polyurethane.

MattisLind
February 28th, 2019, 09:33 PM
Before I start on these next two, is there anything I could use to gently remove a stuck tension band from the tape without destroying the oxide layer?

I was successful recovering som thirty DEC TU58 DECtape II cartridges. To remove the stuck belt I used hot air desoldering station turned to the lowest temperature. From som distance I the blew the hot air onto the belt. One could see how the surface changed from matte to blank. Some times the belt snapped off just by the gentle heat.

I learnt this method from Rik Bos and it worked very well for these tapes.

There were som residue left on the tape coming from the belt which I gently cleaned with som Isopropanol. I also cleaned all the metallic tape guides and but som new grease to roller hubs.

I had problem with quite som tapes that some kind of white crystaline stuff had developed. This would cause the tape to stick to the tape guides. I cleaned the back of the tape in this area with Isopropanol.

Finally I replaced the belt with a new Plastiband type belt.

I was able to recover all but 1 tape. But that one had a damage to the tape not caused by the belt.
No, I did not bake the tapes prior to all this.

Good luck!

MattisLind
February 28th, 2019, 10:01 PM
Sorry about the typos in the previos post. Phones are not great devices for writing and the edit time limit expired so quickly...

Al Kossow
March 1st, 2019, 07:13 AM
I had problem with quite som tapes that some kind of white crystaline stuff had developed. This would cause the tape to stick to the tape guides. I cleaned the back of the tape in this area with Isopropanol.


If you are working with 1/4" tape, it is possible to glue lint free cloth to the guides to keep the tape from sticking. It spreads the gunk across the cloth instead of
in a narrow spot. The cloths I'm using were from a stack from an old unisys tape drive cleaning kit

51469

I've been posting a whole thread about this on my twitter feed @bitsavers as I've been working through tapes

The latest thing I discovered is you need to keep the cloth away from the edges of the tape guide, or it will shave a tiny bit of tape off the edge
when retensioning.

The other bit of magic was finding an adhesive. Aleene's Fabric Fusion from a craft store works really well. It is a glue that gets tacky quickly.
You apply a drop to one edge of the cloth, apply it to the back of the post then pull the cloth a little to spread it out over the back, let it get
sticky and wrap the other end of the cloth around the post.

The other bit of magic was cutting the strips. An old paper cutter works if you push the blade towards the cutting table to get a clean cut

51471

It is possible to reuse the modified base plates multiple times if the gunk accumulation isn't too bad.
Baking makes a HUGE difference in shed. Without baking with 80's Scotch thin tape, there is so much shed
that it still sticks.