Here is Dan’s reply - this method saved our biscuits a few times. But first to My Haley - While not archival inherently due to the ATRAC encoding, as Dan says below, the MDs are extremely robust as far as data longevity is concerned. That’s why I kept a half dozen of the decks when our studio was dismantled!

Dan wrote:

Lou -- Pls forward to list:

It's been a while. But if memory serves. this is how we've done it in the past:

a) Using a Tascam MD-801R MiniDisc machine, which, as I recall, could repair TOCs:

b) Using two decks and swapping transports, like so:

If you have two identical MD decks (preferably Sony MDS-302 or similar):

- Remove the housings and see what's involved in removing and replacing the transport mechanisms -- i.e., removing the screws that anchor the transport, pulling the ribbon-cable plugs, etc. Try it once to be sure it's doable on your particular deck.

- On a fresh disc, record a single, continuous track that fills the disc. Content is unimportant. This will be the "donor" disc that will provide the fresh TOC.

- Load the defective disc into deck A, and the new TOC disc into deck B. Wait until the decks read the TOCs as best they can.

- Pull the AC plugs on both discs. (This will force a TOC write when the decks are next powered up.)

- Swap the drives temporarily between the two decks but do NOT anchor or connect the drives, or power up the decks yet.

- On the deck that now contains the defective disc: Connect the drive, anchor it, and power up the deck. The deck will now write the good TOC to the disc.

- Eject the repaired disc.

- Replace the drives in their original decks.

- Eject the donor disc.

- Replace the housings on both decks.

That should do the job. NOTE: The repaired disc will have all its content in one continuous track, so after transferring it to a single audio file you'll have to separate the tracks 

In their day, magneto-optical discs (like MDs) were the most archivally robust medium available -- theoretically they should last forever. But this TOC issue did arise from time to time, and it did bite us in the behind now and then.

Good luck, and let us know how it goes!

Dan Drasin
Operations Manager
New Dimensions Radio

Lou Judson
Intuitive Audio

On Aug 9, 2016, at 2:36 PM, Richard L. Hess <[log in to unmask]> wrote:

> Thanks, Lou and John!
> I thought that migration had taken place, but this came out of the blue.
> When I hear from your friend, Lou, I will pass it on to the original inquirer.
> On 8/9/2016 5:22 PM, John Haley wrote:
>> Minidiscs are by now an odd format, and players that can deal with both its
>> technical playback and its proprietary, "computer driven" data-reduction
>> system are going to be very hard to find before long.  They were never a
>> great means for archiving anything, as they are inherently lossy.  That was
>> an intentional part of the design.  All data stored on minidiscs that has
>> any value should be migrated to regular CD format.
>> Best,
>> John Haley
>> On Tue, Aug 9, 2016 at 5:06 PM, Lou Judson wrote:
>>> I have a friend who has a trusted method of doing this. It involves
>>> swapping out the transport while a good TOC is in memory. I’m Bcc ing him
>>> and if he can do it, will let you know!
>>> <L>
>>> Lou Judson
>>> Intuitive Audio
>>> 415-883-2689
>>> On Aug 9, 2016, at 2:00 PM, Richard L. Hess wrote:
>>>> Hi, all,
>>>> As you know, I attempt to have an index to cover as many formats as
>>> possible on my website and for the minidisk, I have the material below,
>>> which prompted a potential client to ask:
>>>> I wondered if you had any updated contacts for people that might be able
>>> to ​recover music from a MiniDisc with an unwritten TOC file.
>>>> It appears that the people offering this as a service in Bristol England
>>> have closed down.
>>>> I think this needs an update. Badly.
> -- 
> Richard L. Hess                   email: [log in to unmask]
> Aurora, Ontario, Canada                             647 479 2800
> Quality tape transfers -- even from hard-to-play tapes.