Sound is only coming when the bass volume knob in son Full

Hi, I have an old Home Theatre System 5.1 Surround, I recently changed it to one of the main IC TDA2030, and everything looks great, it's just the bass/bass volume knob.

It is not giving any sound when It is halfway, the only way I get any sound from the bass/subwoofer is when I'm on full volume.
Is there any fix to that, also my BASS IC is good, I have tested it through a direct connection it works well.
I am not sure if the bass volume knob is bad or something else.