Denon CD receiver and MD (Langney BN23)

Denon UD-M30 CD receiver with separate Denon DMD-M30 mini disc recorder, plus remote control and operating instructions.
Receiver works but occasionally the volume increases for no apparent reason other than that it works well. Possibly an easy fix?
MD player has not been used for quite some time but was working perfectly when last used.
Please note, MD player only works when connected to the CD receiver.
I have some, but maybe not all connecting cables but these can be obtained easily enough.