Speed and volume issues

Problem Description:Increase and decrease of Speed and volume

Reason Analysis:

1)Speed and volume can only be increased but not decreased

2) No response to speed or volume increase or decrease

Solution:

1) The speed or volume knob is loose, you need to open the upper case and reinstall the knob, or replace the knob.

2) Check whether the communication wire of the knob is loose, and insert the wire tightly.