This is just a little story about a Sharp MD-MS200 MiniDisc recorder that tried to attack a concrete floor. For some pictures of the inside of an MS200 please see my Inside the MS200 article.
After playing around with both the heads I put everything back together and tried it out. After everything I'd done to it, disks still played without a problem, but recording wouldn't work yet; I got a "LOCK ERROR" message. Incidently, I discovered a new function while I was testing out the recording of my MS200. All functions are disabled when the MS200 detects a UTOC ERROR, except the ERASE ALL function which allows you to overwrite the damaged UTOC. Pressing and holding the EDIT button will give you the prompt ALL ERASE?. Rather than damage the UTOC on all my disks to test the recording, I just repeatedly tried clearing the UTOC on the disk that had already been damaged.
I took everything apart again, looking this time at the locking mechanism, which is intended to prevent the disk from being removed when there's an impending TOC update. It turns out that the same mechanism is used to lock the eject lever and lower the magnetic head onto the disk surface. This means that if you record tracks and then play the disk before shutting of the recorder (which causes it to perform the TOC update), the head will remain in contact with the disk surface while playing. While the damage this causes to this disk and head is probably minimal, you may be able to increase the life of your recording head by always updating the TOC imediately after making a recording (which is a good idea anyway). I couldn't see anything wrong with the locking mechanism, so I just manually moved it through the cycle couple of times and put everything back together.
Yahh! Recording worked! After successfuly clearing the TOC on the damaged disk, I chose the main theme from Star Wars to be my first test recording, and it worked beautifully. Two weeks later, my MS200 is still playing and recording without any problem. The real test of whether or not everything is properly realigned will be trying to play disks that have been recorded on my MS200 on someone else's machine. I don't suspect this will be a problem though.
The moral of this story: Don't drop portable MiniDisc recorders! They're durable enough to take quite a lot of abuse, even durable enough to withstand having me poke around inside, but they're not invulnerable. I encourage other people to try taking apart their MiniDisc recorders, but don't start fooling around with the read/write heads like I did. This was the act of a desperate person! I'm still quite surprised that I was able to get it working at all.