How can a MiniDisc just erase itself?!?!?!

[Beagle]

It's happened twice now, an MD I've recorded reads 'Blank Disc" when I put in on. It's erased itself somehow. I don't know how, it was just sitting with the rest of my MD's. I did note that both MD's affected were ones that had no outer plastic holder case, they came in a plastic box of 5 and had no individual plastic cases.

But I am at a loss as to how two of them could just suddenly become blank. I did put a temporary yellow sticky label on the front but how could that erase an MD?

I was very upset last night because in March I had recorded a 25th anniversary radio station "party" live on air with lots of cool stuff and now it's gone forever.

If I'd done it on a cassette I'd still have it...

 

[Braver]

well, if something in the TableOfContent gets screwed up, the MD could read as 'empty'.

it could also be the fault of the MDP, not reading the TOC properly. have you tried an other player? and are you confident you actually recorded something (happened to me once

)?

before dismissing the disc, I'd try and find another player.

 

[disturbed]

Relax

You might have made the most common mistake everyone does

After you finish recording something DO NOT just eject the disk and pop in another one.

Instead press the stop button ... let the "TOC EDIT" finish ... then ... you eject.

I screwed up so many times before. I lost one very important 2.5hr financial lecture because I didn't let the TOC EDIT finish.

Hope this helps

 

[Braver]

my Sharp MDP won't let you open it when it hasn't finished writing the TOC, very handy feature.

 

[Beagle]

Thanks braver and disturbed, but it's none of the above.

I tried the discs on my MZ-R50 portable and my home deck. Both read "blank disc". And as you stated on your last post braver, I can't eject a freshly recorded disc until the info has been saved, it's a safety feature, on both.

And yes, I did have stuff on the disc, I had already listened to part of it (recorded 2 months ago) and labeled it.

I still wonder if it's because those two particular discs were not in outer plastic protective cases. But I still can't understand how the info could just disappear.

 

[Joe Bloggs]

>> well, if something in the TableOfContent gets screwed up, the MD could read as 'empty'.

Your most likely possibility perhaps?

Are there data recovery companies that work with MDs?

Joe
Never touched an MD

 

[Beagle]

I know, eh? And people complain that the analog cassette loses high frequencies after time?!?! At least when you go to listen to it it's there !

 

[gloco]

Quote:

Originally posted by Beagle I still wonder if it's because those two particular discs were not in outer plastic protective cases. But I still can't understand how the info could just disappear.

Based on three years of experience and leaving Md's out of their cases for several months, the only thing that ever happened to my MD's were drop outs...drop outs that embedded themselves onto the disc and rendered them useless. For a whole disc to wipe itself out something must have happened to that MD, was it exposed to heat? Did you sit these MD's on top of your MD deck (cuz u know it gets quite hot on top), were the discs exposed to severe weather, like cold, hot or humid? Were the discs exposed to contaminants (dust, dirt, cooking grease...in the air) that may cause the disc not to function any longer? Lastly, does your MD deck work well? I know the last deck i had was so screwed up it messed up a lot of my MD's during recording (adding drop outs) and physically.

At first, i couldn't figure out why my MD's all crapped out on me, but it turned out to be a host of things I did wrong.

 

[Beagle]

Thanks gloco...

I keep my MD's near my Grado RA-1 amp which I sometimes use with my MZ-R50. But I've always done this. I have had the MD's fall on the floor on occasion (a 2 foot drop) but they worked OK after. I don't see anything in the manual indicating that the MD should be kept away from electrionics or speakers etc.

 

[thomas]

There is probably only a small bit error in the TOC (table of contents), making the players mistake the disc for a blank disc. However, it is extremely unlikely that the rest of the audio data was affected, unless you have huge magnetic fields/high temperatures in hour house

the solution? clone the TOC

To do so, you must find an MD player that can be defeated, see www.minidisc.org under "hacking"

Basically, you trick the MD player into thinking that the disc drive is closed, by taping over the limit switch that senses the door position. Then, insert a blank MD, and let it record from beginning to end, filling up all 74 minutes. Then, before powering down, you swap the discs, putting in the damaged one (since the sensor is closed, it doesn't know the disc has been changed), and then power down. The MD player will write the new 74 minute TOC to the disc, replacing the corrupted version...

EDIT: oops, forgot, the disc drive is locked- So the correct order is: record the 74 minutes, power down, tape down the limit switch, power up, change discs, do one small random edit on the damaged disc, then power down again....

Finally, restart the MD player, and use its editing features to divide up the tracks again...

It isn't very hard to do, though it would be much quicker to re-record the original disc unless you had rare/live recordings on those discs...

 

[Beagle]

Quote:

Originally posted by thomas Basically, you trick the MD player into thinking that the disc drive is closed, by taping over the limit switch that senses the door position. Then, insert a blank MD, and let it record from beginning to end, filling up all 74 minutes. Then, before powering down, you swap the discs, putting in the damaged one (since the sensor is closed, it doesn't know the disc has been changed), and then power down. The MD player will write the new 74 minute TOC to the disc, replacing the corrupted version...

Thanks very much thomas, that's quite something. Unfortunately, figuring that the info was gone, I reused the affected MD and now the stuff that was on there is history. Arrgghh!

I'm not quite clear on this part... Quote:

The MD player will write the new 74 minute TOC to the disc, replacing the corrupted version

If it writes the new 74 minute TOC onto the damaged disc, is that new TOC not the TOC of the new recording?

I think I may have an idea what might have contributed to the problem. As I mentioned, these particular discs were "loose" and I had stuck a small yellow post-it note on the front listing what I recorded. It didn't affect play or recording on the others but it did on these two. I may have blocked the path for the laser to reflect.

Anyway, thanks a lot for those helpful suggestions, at least there is a method of salvaging if I run into the problem again.

 

[MacDEF]

Quote:

Originally posted by Beagle I'm not quite clear on this part...If it writes the new 74 minute TOC onto the damaged disc, is that new TOC not the TOC of the new recording?

Right... so you record a single track onto a blank disc (74 or 80 minutes long -- you have to use the same size MD as your original). When you clone the TOC of this new disc to the old disc, you get a disc that has all of the prior contents, but with the TOC of the new disc. Your player then thinks your old disc contains one long track.

Since MDs work like any other data drive, the data is there until you actually overwrite it. So this procedure is basically a way to salvage the contents of a disc by writing a new directory that allows you to access the content. What you do then is manually add track marks (by listening to the MD and placing a track mark between songs/content.

 

[Beagle]

Quote:

Originally posted by MacDEF Right... so you record a single track onto a blank disc (74 or 80 minutes long -- you have to use the same size MD as your original). When you clone the TOC of this new disc to the old disc, you get a disc that has all of the prior contents, but with the TOC of the new disc. Your player then thinks your old disc contains one long track. Since MDs work like any other data drive, the data is there until you actually overwrite it. So this procedure is basically a way to salvage the contents of a disc by writing a new directory that allows you to access the content. What you do then is manually add track marks (by listening to the MD and placing a track mark between songs/content.

OK, I get it. You are simply "installing" a new TOC on the damaged disc so that the MD player can access the data on the disc.

Stupid me, I had it in my head that the data was gone and I reused the disc, and I can never get that stuff ever again, it was a live radio broadcast..

 

[lini]

thomas/MacDEF: So if I got that right, that method will only work for saving minidisks, that aren't fragmented yet, does it?

Greetings from Munich!

Manfred / Lini

 

[thomas]

Yep, it will work the best with a disc that isn't fragmented...

But you can still use it on a fragmented disc, but everything will be in one track, and totally out of order... So you must divide the individual fragments into individual tracks, and re-arrange them manually.... Very time consuming, but possible...