Linn Karik CD transport : Display always enters sleep mode after 20 sec

I have my beloved Linn Karik CD transport for 20 years now and only recently I had to replace it with another one.
Strangely I have the following phenomena:
Display always enters sleep mode after 20 sec. It is not suppose to enter sleep mode when the display switch (back panel) is out . Is there a jumper on the PCB that is relevant to the issue ?
Here is the relevant section from the manual...

 "SLEEP MODE
If the DISPLAY switch on the back panel is in, and power is applied, the KARIK will enter a ‘sleep’ mode. Twenty seconds after the last operation the display will turn off (show two dashes). Actuation of the door, front panel controls or remote control will waken the display. This feature, shared by the Linn Kairn pre-amplifier and Kremlin tuner, saves power and draws less attention to the products, if required. When the display switch is out, and power is re-applied, the display will remain lit continuously. "