I have a friend that has a Denon DN-M2300R that has trouble dealing with 80 minute discs in the #2 (recorder slot). I also have a Sony MDS-B4P broadcast MD cart player which I think has the same condition. Am I right in thinking that some of the older equipment, including professional equipment, were marketed before the 80 minute MD was introduced and therefore have trouble with those discs? If so, it might be a good idea for minidisc.org to tabulate those particular machines.