Anyone understand DAT machines??? (Tech question)

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RFR

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Ok here’s the deal.

Perfectly functioning DA30. Taken out of use for remodel. One year.

Plug it in and find out I had a left a Dat tape inside. It came out with part of the tape exposed. (Like when your cassette deck tries to eat your tape)

Test it out with another tape. Music plays but with weird digital distortion throughout.

Did this on other tapes as well.

Some say that dat tapes can go bad, but all these tapes are 25+ years old with no issues.

I can’t believe that a tape that performed well all this time could suddenly go bad in a years time.
Same climate, same storage method, not around any magnets etc.

Clean the head? How? I’ve heard you can’t clean them like you would an analog deck

I appreciate any insight someone might have.

I haven’t tested recording and playback since I don’t have a new blank tape

Thanks
 
Cleaning would be my 1st course of action. If you don't have a cleaning tape, which will often work in a pinch, you need to open the unit up. Never use cotton swabs on a DAT. You need non-shedding foam or shammy-tipped swabs moistened with a good head cleaner. Clean the capstan & guides. Hold a swab against the rotating head and turn the head from the top in one direction. Don't scrub up & down. A bit of rubber cleaner on the pinch roller wouldn't hurt either.
 
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Hey thanks for responding!

Would those foam makeup applicators work.

I’ll steal one from my girl ?
 
Cleaning the head and tape path seems like a good idea. A tape left in that long may have been in contact with a lot of those parts and left substantial residue.
 
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The cleaners that come in a can with a long nozzle swoosh the muck away. A friend swears by the little superglue containers that have the really long tiny tube extensions. Put IPA in the bottle, the put the tube against the head slot and squeeze hard. The pressure does the work, but the thin bore means little comes out and then it evaporates.
 
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RFR said:
Hey thanks for responding!

Would those foam makeup applicators work.

I’ll steal one from my girl ?
Click to expand...
I don't know. See how they behave when moistened with head cleaner. If they shed or fall apart, then no. Make sure they are by themselves chemical free.
 
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Teac specified " clean lint free cloth" - they used something from Japan called Minmax, a tightly woven plastic cloth- feels like silk- with 91% IPA or denatured.. No rubbing alcohol @70 % with added Lanolin, no head cleaner- the heads are resin-, no foam swabs, no texwipes, as they can snag the heads and knock them out of alignment as the heads float in the gap in the upper drum. If nothing else run a new tape FFWD to the end and RWD. Never move the cleaning media up or down while in contact with the heads, and rotate the drum in the direction it spins- counterclockwise.
 
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wkrbee said:
Teac specified " clean lint free cloth" - they used something from Japan called Minmax, a tightly woven plastic cloth- feels like silk- with 91% IPA or denatured.. No rubbing alcohol @70 % with added Lanolin, no head cleaner- the heads are resin-, no foam swabs, no texwipes, as they can snag the heads and knock them out of alignment as the heads float in the gap in the upper drum. If nothing else run a new tape FFWD to the end and RWD. Never move the cleaning media up or down while in contact with the heads, and rotate the drum in the direction it spins- counterclockwise.
Click to expand...
Thanks, that’s some detail. ?

I’m getting the idea that the heads are multiple, and are tiny ass things in the slots on the drum.

I wish I had a destroyed DAT machine that I could take apart just to study it.
 
wkrbee said:
Teac specified " clean lint free cloth" - they used something from Japan called Minmax, a tightly woven plastic cloth- feels like silk- with 91% IPA or denatured.. No rubbing alcohol @70 % with added Lanolin, no head cleaner- the heads are resin-, no foam swabs, no texwipes, as they can snag the heads and knock them out of alignment as the heads float in the gap in the upper drum. If nothing else run a new tape FFWD to the end and RWD. Never move the cleaning media up or down while in contact with the heads, and rotate the drum in the direction it spins- counterclockwise.
Click to expand...
Question, if the heads are ‘floating’ wouldn’t anything knock them out of alignment?
 
Not just move them out of alignment, break the damn things off! Rotary video heads could take a decent amount of cleaning effort side to side, but up and down, they died instantly! DAT got even smaller and far more difficult to clean. cotton wool on a stick killed a large number! Remember there is dirt on the top, and that comes off pretty easily, but the harder deposits either side of the head in the gap get harder like the stuff you get on your teeth if you don't brush properly = and that is hard, and lifts the tape up and contact is lost.
 
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Dat machines are nothing more that small VCR type decks. The Helical scan heads are very sensitive to pressure. The item we used at VCA Teletronix where we did 8 hours a day VCR cleaning and other repairs we use Text Wipes. The chemical we used was called Fedron and I think it was too strong but was on the heads for just a second or two. I have cleaned video heads with Denatured. Isopropyl again does not have enough strength. So far I have worked on real cheap $99 VCR all the way up to DVR22 which is $55,000 per unit. In all cases you need to be careful and cleaning of head is not the only thing- guides and the Pinch roller and capstan shaft accumulate a lot of particles and these particle when left in the machine cause pin holes in the tape surface and these cause drop outs. The drop out compensator can only go so far so when the clean indicator is on in the window if it has one then it has exceeded that level. DAT is a media to get away from as suggested to me by Richard Hess in 2007. When there are no more working ones and no more parts no one will be fixing them.
 
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@skywaveTDR
Thanks. But it’s a bit of a bummer to have an almost obsolete format. I’ve got lots of dat masters not yet transferred.

Gotta find some of those swabs.
 
Shure hope external SSD drives don’t become obsolete too.

Seems like it’s all only temporary.

Over the years I’ve lost so much. Even have some synth music on floppy discs that was done on a commodore 65

Remember those?

Got music on minidiscs too.


Everything goes bye bye. I get what Steve Albini is talking about when he only wants tape.

But tape has its own issues.


Thank god I don’t have any wire recordings

?
 
Skywave is dead on. It is often helpful to understand how it works to understand cleaning and what parts are the most sensitive and where to be the most careful. The DAT works much like this graphic except the video track is the PCM digital audio, there is no analog audio track like VHS but does have a control track the sync's the head with the helical tracks. The heads themselves are a small coil made from extremely fine wire. The location is where there is a little gap on two opposite sides of the drum head A & B. Each head has two head coils with a gap between that can get clogged with dirt and tape coatings. That is the part that the greatest care must be given. You don't want to use a solvent that will damage the coating that seals the wire but need something strong enough to clean away the crud. From there you clean all the parts of the tape path. There will be a rubber pinch roller. This should be cleaned with a cleaner conditioner made for pinch rollers. The head image below is a video head with audio heads for HiFi audio which is recorded by the drum vs the audio head that is part of the control head assembly.

Screen Shot 04-09-22 at 10.52 PM.webp
Screen Shot 04-09-22 at 10.59 PM.webp
 
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Thanks, that was some detail. At worst I’m learning about these machines. At best I can fix them. ?

I’ve gotten a lot of good info from you fine folks, and have been studying YouTube videos.

Now, this current path is assuming that the audio distortions (weird digital noise) is the cause of tape residue and gunk on the heads and tape path from having a tape sit in there for so long. I haven’t opened the da30 yet. Everything else on the machine seems to work just fine

I’m in another rabbit hole right now.

To check and make sure it was the machine rather than my tapes suddenly gone bad.....

I put one into my da30 Markll . Oh boy! At first the tray just opened and closed. After repeated tries, that works fine again. But it has an error one message and the tape won’t play. (This machine worked fine a year ago too)

Since I had a new set of belts handy I took this one apart to work on.

So, we have two non functioning machines, and tapes distorting on playback.

Currently I don’t know which is the culprit.
Fun, fun, fun.
 
Video heads and DAT too can be cleaned with a business card back with denatured solvent on it. The drum is rotated around with not a lot of pressure applied. If you have a head that presents the feeling that it is a snag then it might already be broken. Changing heads is more than just screwing some on. There is an eccentricity adjustment and that is done using a special feeler gauge that measured when the drum sticks out in roundness. This can be a toucht adjustment but when you get it very small and there is a limit to how small you can get it the amount of Dihedral error is reduced. Video or DAT is all a combination of things happening together correctly. On VHS there is a rabid guide that can wear and also have oxide in it. This is where the wood of cotton swabs is used as wood is still soft next to aluminum but care must be taken around the heads- the rabid trace starts near the heads so the drum should be rotated 90 degrees away from that point when cleaning with a wood stick. I went into a shop in Chicago and watch a supposed technician clean a DAT head with a cotton swab while it was rotating- It was under warranty so I did not say anything as he was suppose to be the expert.
 
On the Preamp PCB there is usually a test point to look at the pattern off the heads. If one side is missing then you either have a clog or a broken head. Lacquer thinner or anything that would upset the enamel wire coating is not the stuff to use. Denatured is safe as I have used it for many years with no problem. We had a bit of apprehension when we changed the drum on a DVR22 deck. The Drum was $3500 and the brush assembly was $1000 but those prices are low if they still offer the parts. It cost some money to play with the big toys.
 
Sounds complicated.
What’s a DVR22? Did a google search and it came up with flight trackers
 
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