The manuals for the 1800 etc are on - to alter the speed, there are two variable resistors on PCB 2 which is situated under the arm - I think there are two access holes under the bottom of the deck. Look at page 1-1 and 5-1 for the laction. Service manuals are always a bit terse as they exect you to know things not in the manual!! This one is actuallly quite helpful for B&O!