Found this in the manual:
19.4 Output Socket Selection
A pair of RCA Phono output sockets are fitted on CD player rear panels to provide an alternative to the preferred DIN socket. Proceed as follows to select the RCA Phono sockets.
With the player stopped, press and hold the remote handset disp function (handset in CD mode) or, if fitted, the player disp button until the CD player prog indicator flashes. Further operations of the disp function will now cycle through each combination of the two socket types (DIN only, RCA Phono only or both). The selected option is indicated on the CD player display as shown below.
S
ocket Option Player Display
DIN O
Phono
Both O
Press and hold the disp function a second time to exit from socket selection mode.
To avoid compromised sound quality, do not select both unless their simultaneous use is unavoidable.
Make sure you have the right outputs selected. Also, if the remote has volume controls on it, make sure they are turned all the way up. The RCA outputs might be variable.
19.4 Output Socket Selection
A pair of RCA Phono output sockets are fitted on CD player rear panels to provide an alternative to the preferred DIN socket. Proceed as follows to select the RCA Phono sockets.
With the player stopped, press and hold the remote handset disp function (handset in CD mode) or, if fitted, the player disp button until the CD player prog indicator flashes. Further operations of the disp function will now cycle through each combination of the two socket types (DIN only, RCA Phono only or both). The selected option is indicated on the CD player display as shown below.
S
ocket Option Player Display
DIN O
Phono
Both O
Press and hold the disp function a second time to exit from socket selection mode.
To avoid compromised sound quality, do not select both unless their simultaneous use is unavoidable.
Make sure you have the right outputs selected. Also, if the remote has volume controls on it, make sure they are turned all the way up. The RCA outputs might be variable.