In article ,
Lucifer wrote:
I have a Denon DMD-M10 minidisk recorder that will not play disks
recorded on other machines nor will it record on a disk that has been
used before. I was able to record on an unused disk which does play.

At a guess, I'd suspect that it might be any of the typical faults
which can develop in any laser-optical-based disc recording and
playback system:

- Deteriorating laser (lower output level)
- Dirty laser or read-back optics (dust, tobacco or cannabis smoke
particles and tar)
- Dirty or poorly-lubricated "sled" on which the optical assembly moves
- Misadjusted servo tracking system

Power-supply problems e.g. deteriorating filter capacitors, loose
cables, intermittent contacts, etc. can also be a problem as these
devices age.

None of the above is at all specific to your recorder model. If
you're serious about trying to fix it, I'd suggest getting the
model-specific service manual (there's one up on eBay from a seller in
Florida - no connection).