the synth:
below, Volume and Tempo pots are shown, these are (extremely) floating but working, and need to be replaced asap.
all help with identifying/advising where these could be obtained, will be gladly accepted and appreciated! :
(query to rolandus tech service support opened) …
which manufacturer is this?

they are either ALPS or alps like ‘copys’.. the ones you are looking for should be on this page somewhere:
http://www3.alps.com/WebObjects/catalog.woa/E/HTML/Potentiometer/InsulatedShaft/InsulatedShaft_list1.html
there’ll be some characters on those pots somewhere indicating part number/value ..find these out and youll be able to find a replacement far easier.
heres one place that sells this kind of potentiometer:
http://uk.farnell.com/1191725/passives/product.us0?sku=alps-rk09k11310kb