There are three possible causes.

1. Have you pressed a [SOUND COLOR FX] button and selected an effect? Press the [SOUND COLOR FX] button and select the effect you want to apply.

2. Is the [SOUND COLOR FX] [BEAT] button set to [ON]? Press the [SOUND COLOR FX] [BEAT] button to set it to [ON].

3. Is the [COLOR] control set to an appropriate position? Turn the [COLOR] control clockwise or counterclockwise.

Also, depending on the track being input, the [BEAT COLOR FX] effect may be hard to distinguish.