It's probably the micro switch not detecting the MiniDisc:
http://members.tripod.com/~snnake11/

Jos

"Yde" schreef in bericht
. ..
Hello,

I've bought a goodlooking second-hand mds-501. The minidisk has one
problem.
When starting for the first time the unit won't accept the disc. The disc
starts turning but the laserunit does not move.
I've to place it vertical on the side of the powerbutton. When he
recognices
it I can place it horizontal again. After playing or recording the first
minidisk the problem seems to be over. I can play or record for hours
without a problem but the next day the problem is back.
Problems with a switch?? Heath problem. (when the unit is warm after a
while it works perfectly )
Any suggestions??

Thanks in advance. Yde