PIONEER DJ DJM-750MK2 Operating Instructions Manual page 26

Problem
Sound is distorted when an analog
player is connected to the [PHONO]
terminals.
Or, lighting of the channel level
indicator does not change when the
[TRIM] control is turned.
26
En
Check
Is an analog player with a built-in phono equalizer
connected to this unit?
Is an audio interface for computers connected
between the analog player and this unit?
Remedy
Connect an analog player with a built-in phono equalizer to the [LINE] terminals.
(page 7 )
Set the PHONO/LINE selector switch on the analog player to PHONO if
available.
If the output of the audio interface for computers is line level, connect it to the
[LINE] terminals. (page 7 )
Set the PHONO/LINE selector switch on the analog player to PHONO if
available.