baking TKx0 tapes

[hush]

hey all! i have a collection of TK50 and TK70 tapes that i'd like to go through, i plan on reusing them if possible but i'd like to make sure there's nothing interesting or useful on them first. most of them are exhibiting errors that i don't believe are related to the drive or the controller. for instance, a TK70 tape i was able to read a few days ago now exhibits the following error, while i was able to read a TK50 tape:

$ back/rew/list mua0:
Listing of save set(s)

%MOUNT-I-MOUNTED,  mounted on _WOOYOO$MUA0:
%BACKUP-F-LABELERR, error in tape label processing on MUA0:[000000].;
-BACKUP-F-NOTANSI, tape is not valid ANSI format

does anyone have specific suggestions for baking TKx0 tapes? based on my reading 45C for 8 hours should do it, but i figured i would ask before trying anything stupid.

thanks!

 

[Al Kossow]

I have never successfully disassembled and reassembled one of those cartridges.

 

[leegleason]

That looks like an unused tape. For tapes that act funny, try mounting them /FOREIGN and then use DUMP to have a look at the first few blocks (if any) to see what kind of stuff is written on it (if anything).

 

[hush]

That looks like an unused tape. For tapes that act funny, try mounting them /FOREIGN and then use DUMP to have a look at the first few blocks (if any) to see what kind of stuff is written on it (if anything).

it is not an unused tape...

"for instance, a TK70 tape i was able to read a few days ago now exhibits the following error"

will try DUMP later today

 

[F11ACP]

> was able to read a few days ago now exhibits the following error

I'd say it was your last (and only) chance to read the tape. Old tapes are not something that can be used over and over again. The ferrous oxide layer was probably unstable and was damaged by the previous (successful) read, and the cartridge is as good as a paper weight now.
Also, your tape drive's head can be smudged with the (dislodged) residue and should now be cleaned. I only hope that you saved an image of the tape (the first time you read it) or there was nothing important on it.
Sorry about the bad news.

 

[hush]

> was able to read a few days ago now exhibits the following error

I'd say it was your last (and only) chance to read the tape. Old tapes are not something that can be used over and over again. The ferrous oxide layer was probably unstable and was damaged by the previous (successful) read, and the cartridge is as good as a paper weight now.
Also, your tape drive's head can be smudged with the (dislodged) residue and should now be cleaned. I only hope that you saved an image of the tape (the first time you read it) or there was nothing important on it.
Sorry about the bad news.

the drive only had backups from what appeared to be someone's warehouse inventory/order system, more than likely to be personal/useless data which is why i was using it as a test tape. i just checked the head of the TK70 and there is no residue, a qtip swabbed in 90% iso came back almost completely clean save for some light brown dust/dirt. is it possible something else could be going on?

 

[F11ACP]

Do you have a fresh (new) cartridge that you can use to write a backup on it from the working system? Can it be read back / listed successfully / reliably? Just to rule-out that the tape drive is not the culprit.

 

[hush]

Do you have a fresh (new) cartridge that you can use to write a backup on it from the working system? Can it be read back / listed successfully / reliably? Just to rule-out that the tape drive is not the culprit.

i do not, all the tapes i've found and all the ones i have are used

 

[F11ACP]

Maybe you can try using one of the old tapes (which you saved previously) -- and see if that's any reliable with writing and reading it back.

 

[hush]

Maybe you can try using one of the old tapes (which you saved previously) -- and see if that's any reliable with writing and reading it back.

no dice on that:

$ ini mua0: testbk
%INIT-F-PARITY, parity error

this was on the TK70 tape that originally read fine

 

[F11ACP]

Yeah, unfortunately, you can't rule-out the device with that... Unless you're lucky to find another working TK70 somewhere ;-)

 

[bigfix]

I used 60 degree Centigrade for 4 hrs with sticky TK50 Tapes
After this I could read 20 out of 22 Tapes written 25 years ago
TLZ04 DAT Tapes of similar age all worked without baking

 

[Al Kossow]

I have a LOT of experience over 20 years with tape recovery, processing
literally thousands of tapes.

I'm amazed that worked at all.
With the tape sealed, there is no air circulation and that
is absolutely required to get the water out of the media.

I learned that in the 00's trying baking w/o airflow. Someone
else back then who already had a lot of experience recovering
old 7track tapes warned me about the airflow issue.

The whole point of baking is to try to reduce sticky-shed
due to the binder formulations being hydroscopic. Now, think
about what is required to dehumidify a tape reel. You have to have
exposure to the edges, and a LOT of air.

I use a commercial food dehydrator for QIC tapes, with just the base plate
and supply reel left on it. For 1/2" tape I have a modified dehydration chamber
with a large fan bank and heater forcing air up through the flanges.

I've really had very little luck with DLT recovery because I couldn't get the
cartridges disassembled to evaluate the condition of the tape of see what
affect baking would even have on the formulations used on that tape.

 

[antiquekid3]

If one had access to a vacuum oven, I would think that would work very well and would allow for reduced temperature if you pulled enough vacuum, yes? Long enough bake time should help reduce air circulation requirements since the pressure is so low. Any idea if this has been tried?

 

[bear]

I'm amazed that worked at all.
With the tape sealed, there is no air circulation and that
is absolutely required to get the water out of the media.

Dunno what to say, I use a non-commercial food dehydrator and have baked hundreds of TK50s in it, giving consistent, demonstrable results (completely counter to my experiences with baking QIC) just by propping the flap open. At this point I'd take a project to process a couple hundred TK50s sooner than one to process a half-dozen QIC.

 

[rjarratt]

I baked a TK50 in a domestic fan oven at 45C, just above its lowest temperature, for 8 hours, with the tape door propped open. It worked for me, but I believe the domestic fan ovens can allow the temperature to vary quite a lot so you need to be careful and it would be wise to monitor the temperature and try a sacrificial tape first.

 

[hush]

this is all good info, thank you all for now i'm going to work on either replacing or repairing the TK70 i have, seems like it's more likely to be the culprit at this point

 

[czunit]

As one of the few people on the planet who actually *USES* TK50's and 70's as primary backup media I have a few.... thoughts.

First, the weak point in these units is the capstains. Specifically the bearings have had their grease/oil dry out and as a result they drag on the tapes. More importantly the rear one is attached to a tachometer and it is CRITICAL that it does not drag or slip. If they drag they wear the tape and have massive problems with reading (as speed is sensed by that rear capstain)

So you need to remove them and either oil the bearings with light then medium viscosity watch oil (which will re-grease the dried grease) or press out and replace the bearings. If you spin them they should spin freely and spin for a bit with just finger flicks. If the drag or stop immediately they ain't gonna work.

Second problem is tape height is *super critical", controlled by the turns of the nuts on top of the capstains, and extremely difficult to set. However you can mark each nut and count the number of turns exactly to remove it. Make sure to note the position when it's at rest and just before it comes off the screw. Then turn the nuts back on the exact number of turns/fractions of a turn and the drive is in alignment. How can it be not

Note: Make sure you remember which nut goes on which spindle, as the marks will be at different places in the threads on the different nuts. Front nut to front capstain, rear to rear, and if there are washers keep the washers with the proper capstain.

When I get a new tape in I run several backups and verifies on it, then I rewind and lift up the head to check for any residue. If I see any residue I junk the tape, it's shedding. No residue=tape goes into the general population box. Keep an eye on the head and which tapes you use, if a tape starts throwing errors check to see if it's shedding, and if so junk that tape, clean the heads and capstains, then check the last tape you used and see if it's now shedding. Go back till you find good tapes, damage can spread from tape to tape.

With that, they're great. I can do things to my system and if I trash the disk I simply pop in an RX01 floppy with bru64k, then do a restore from the tape back to the disk. Never a problem. Also note, the TK70 controller is a lot better than the TK50 and can usually stream backups instead of the endless start/stop of the TK50. And a TQK70 can be used with a TK50 drive.

Have fun!

 

[hush]

As one of the few people on the planet who actually *USES* TK50's and 70's as primary backup media I have a few.... thoughts.

First, the weak point in these units is the capstains. Specifically the bearings have had their grease/oil dry out and as a result they drag on the tapes. More importantly the rear one is attached to a tachometer and it is CRITICAL that it does not drag or slip. If they drag they wear the tape and have massive problems with reading (as speed is sensed by that rear capstain)

So you need to remove them and either oil the bearings with light then medium viscosity watch oil (which will re-grease the dried grease) or press out and replace the bearings. If you spin them they should spin freely and spin for a bit with just finger flicks. If the drag or stop immediately they ain't gonna work.

Second problem is tape height is *super critical", controlled by the turns of the nuts on top of the capstains, and extremely difficult to set. However you can mark each nut and count the number of turns exactly to remove it. Make sure to note the position when it's at rest and just before it comes off the screw. Then turn the nuts back on the exact number of turns/fractions of a turn and the drive is in alignment. How can it be not

Note: Make sure you remember which nut goes on which spindle, as the marks will be at different places in the threads on the different nuts. Front nut to front capstain, rear to rear, and if there are washers keep the washers with the proper capstain.

When I get a new tape in I run several backups and verifies on it, then I rewind and lift up the head to check for any residue. If I see any residue I junk the tape, it's shedding. No residue=tape goes into the general population box. Keep an eye on the head and which tapes you use, if a tape starts throwing errors check to see if it's shedding, and if so junk that tape, clean the heads and capstains, then check the last tape you used and see if it's now shedding. Go back till you find good tapes, damage can spread from tape to tape.

With that, they're great. I can do things to my system and if I trash the disk I simply pop in an RX01 floppy with bru64k, then do a restore from the tape back to the disk. Never a problem. Also note, the TK70 controller is a lot better than the TK50 and can usually stream backups instead of the endless start/stop of the TK50. And a TQK70 can be used with a TK50 drive.

Have fun!

wow, this is a fantastic writeup, thank you! i should actually be able to get it working, soon as i have the spoons :D

 

[czunit]

I've done a few other threads on them. I like the TK70, it's a good looking drive and can back up most of a 330mb ESDI disk on one tape. That's about all I need to have endless fun with an 11.